ent/doc: fix getting started example and add link to Github

Reviewed By: alexsn

Differential Revision: D17734937

fbshipit-source-id: abced88c23b7385d371361c5069292de5c1c5b1e

examples/start/README.md

@@ -0,0 +1,9 @@
+# Getting Started Example
+
+The example from the getting-started page in https://entgo.io.
+
+### Generate Assets
+
+```console
+go generate ./...
+```

examples/start/ent/car.go

@@ -0,0 +1,102 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"bytes"
+	"fmt"
+	"time"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// Car is the model entity for the Car schema.
+type Car struct {
+	config `json:"-"`
+	// ID of the ent.
+	ID int `json:"id,omitempty"`
+	// Model holds the value of the "model" field.
+	Model string `json:"model,omitempty"`
+	// RegisteredAt holds the value of the "registered_at" field.
+	RegisteredAt time.Time `json:"registered_at,omitempty"`
+}
+
+// FromRows scans the sql response data into Car.
+func (c *Car) FromRows(rows *sql.Rows) error {
+	var vc struct {
+		ID           int
+		Model        sql.NullString
+		RegisteredAt sql.NullTime
+	}
+	// the order here should be the same as in the `car.Columns`.
+	if err := rows.Scan(
+		&vc.ID,
+		&vc.Model,
+		&vc.RegisteredAt,
+	); err != nil {
+		return err
+	}
+	c.ID = vc.ID
+	c.Model = vc.Model.String
+	c.RegisteredAt = vc.RegisteredAt.Time
+	return nil
+}
+
+// QueryOwner queries the owner edge of the Car.
+func (c *Car) QueryOwner() *UserQuery {
+	return (&CarClient{c.config}).QueryOwner(c)
+}
+
+// Update returns a builder for updating this Car.
+// Note that, you need to call Car.Unwrap() before calling this method, if this Car
+// was returned from a transaction, and the transaction was committed or rolled back.
+func (c *Car) Update() *CarUpdateOne {
+	return (&CarClient{c.config}).UpdateOne(c)
+}
+
+// Unwrap unwraps the entity that was returned from a transaction after it was closed,
+// so that all next queries will be executed through the driver which created the transaction.
+func (c *Car) Unwrap() *Car {
+	tx, ok := c.config.driver.(*txDriver)
+	if !ok {
+		panic("ent: Car is not a transactional entity")
+	}
+	c.config.driver = tx.drv
+	return c
+}
+
+// String implements the fmt.Stringer.
+func (c *Car) String() string {
+	buf := bytes.NewBuffer(nil)
+	buf.WriteString("Car(")
+	buf.WriteString(fmt.Sprintf("id=%v", c.ID))
+	buf.WriteString(fmt.Sprintf(", model=%v", c.Model))
+	buf.WriteString(fmt.Sprintf(", registered_at=%v", c.RegisteredAt))
+	buf.WriteString(")")
+	return buf.String()
+}
+
+// Cars is a parsable slice of Car.
+type Cars []*Car
+
+// FromRows scans the sql response data into Cars.
+func (c *Cars) FromRows(rows *sql.Rows) error {
+	for rows.Next() {
+		vc := &Car{}
+		if err := vc.FromRows(rows); err != nil {
+			return err
+		}
+		*c = append(*c, vc)
+	}
+	return nil
+}
+
+func (c Cars) config(cfg config) {
+	for i := range c {
+		c[i].config = cfg
+	}
+}

examples/start/ent/car/car.go

@@ -0,0 +1,35 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package car
+
+const (
+	// Label holds the string label denoting the car type in the database.
+	Label = "car"
+	// FieldID holds the string denoting the id field in the database.
+	FieldID = "id"
+	// FieldModel holds the string denoting the model vertex property in the database.
+	FieldModel = "model"
+	// FieldRegisteredAt holds the string denoting the registered_at vertex property in the database.
+	FieldRegisteredAt = "registered_at"
+
+	// Table holds the table name of the car in the database.
+	Table = "cars"
+	// OwnerTable is the table the holds the owner relation/edge.
+	OwnerTable = "cars"
+	// OwnerInverseTable is the table name for the User entity.
+	// It exists in this package in order to avoid circular dependency with the "user" package.
+	OwnerInverseTable = "users"
+	// OwnerColumn is the table column denoting the owner relation/edge.
+	OwnerColumn = "owner_id"
+)
+
+// Columns holds all SQL columns are car fields.
+var Columns = []string{
+	FieldID,
+	FieldModel,
+	FieldRegisteredAt,
+}

examples/start/ent/car/where.go

@@ -0,0 +1,420 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package car
+
+import (
+	"time"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+)
+
+// ID filters vertices based on their identifier.
+func ID(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDEQ applies the EQ predicate on the ID field.
+func IDEQ(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDNEQ applies the NEQ predicate on the ID field.
+func IDNEQ(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDIn applies the In predicate on the ID field.
+func IDIn(ids ...int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(ids) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			v := make([]interface{}, len(ids))
+			for i := range v {
+				v[i] = ids[i]
+			}
+			s.Where(sql.In(s.C(FieldID), v...))
+		},
+	)
+}
+
+// IDNotIn applies the NotIn predicate on the ID field.
+func IDNotIn(ids ...int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(ids) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			v := make([]interface{}, len(ids))
+			for i := range v {
+				v[i] = ids[i]
+			}
+			s.Where(sql.NotIn(s.C(FieldID), v...))
+		},
+	)
+}
+
+// IDGT applies the GT predicate on the ID field.
+func IDGT(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDGTE applies the GTE predicate on the ID field.
+func IDGTE(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDLT applies the LT predicate on the ID field.
+func IDLT(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDLTE applies the LTE predicate on the ID field.
+func IDLTE(id int) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldID), id))
+		},
+	)
+}
+
+// Model applies equality check predicate on the "model" field. It's identical to ModelEQ.
+func Model(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldModel), v))
+		},
+	)
+}
+
+// RegisteredAt applies equality check predicate on the "registered_at" field. It's identical to RegisteredAtEQ.
+func RegisteredAt(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// ModelEQ applies the EQ predicate on the "model" field.
+func ModelEQ(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelNEQ applies the NEQ predicate on the "model" field.
+func ModelNEQ(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelIn applies the In predicate on the "model" field.
+func ModelIn(vs ...string) predicate.Car {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.Car(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.In(s.C(FieldModel), v...))
+		},
+	)
+}
+
+// ModelNotIn applies the NotIn predicate on the "model" field.
+func ModelNotIn(vs ...string) predicate.Car {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.Car(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.NotIn(s.C(FieldModel), v...))
+		},
+	)
+}
+
+// ModelGT applies the GT predicate on the "model" field.
+func ModelGT(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelGTE applies the GTE predicate on the "model" field.
+func ModelGTE(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelLT applies the LT predicate on the "model" field.
+func ModelLT(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelLTE applies the LTE predicate on the "model" field.
+func ModelLTE(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelContains applies the Contains predicate on the "model" field.
+func ModelContains(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.Contains(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelHasPrefix applies the HasPrefix predicate on the "model" field.
+func ModelHasPrefix(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.HasPrefix(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelHasSuffix applies the HasSuffix predicate on the "model" field.
+func ModelHasSuffix(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.HasSuffix(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelEqualFold applies the EqualFold predicate on the "model" field.
+func ModelEqualFold(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EqualFold(s.C(FieldModel), v))
+		},
+	)
+}
+
+// ModelContainsFold applies the ContainsFold predicate on the "model" field.
+func ModelContainsFold(v string) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.ContainsFold(s.C(FieldModel), v))
+		},
+	)
+}
+
+// RegisteredAtEQ applies the EQ predicate on the "registered_at" field.
+func RegisteredAtEQ(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// RegisteredAtNEQ applies the NEQ predicate on the "registered_at" field.
+func RegisteredAtNEQ(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// RegisteredAtIn applies the In predicate on the "registered_at" field.
+func RegisteredAtIn(vs ...time.Time) predicate.Car {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.Car(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.In(s.C(FieldRegisteredAt), v...))
+		},
+	)
+}
+
+// RegisteredAtNotIn applies the NotIn predicate on the "registered_at" field.
+func RegisteredAtNotIn(vs ...time.Time) predicate.Car {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.Car(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.NotIn(s.C(FieldRegisteredAt), v...))
+		},
+	)
+}
+
+// RegisteredAtGT applies the GT predicate on the "registered_at" field.
+func RegisteredAtGT(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// RegisteredAtGTE applies the GTE predicate on the "registered_at" field.
+func RegisteredAtGTE(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// RegisteredAtLT applies the LT predicate on the "registered_at" field.
+func RegisteredAtLT(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// RegisteredAtLTE applies the LTE predicate on the "registered_at" field.
+func RegisteredAtLTE(v time.Time) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldRegisteredAt), v))
+		},
+	)
+}
+
+// HasOwner applies the HasEdge predicate on the "owner" edge.
+func HasOwner() predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			s.Where(sql.NotNull(t1.C(OwnerColumn)))
+		},
+	)
+}
+
+// HasOwnerWith applies the HasEdge predicate on the "owner" edge with a given conditions (other predicates).
+func HasOwnerWith(preds ...predicate.User) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			t2 := sql.Select(FieldID).From(sql.Table(OwnerInverseTable))
+			for _, p := range preds {
+				p(t2)
+			}
+			s.Where(sql.In(t1.C(OwnerColumn), t2))
+		},
+	)
+}
+
+// And groups list of predicates with the AND operator between them.
+func And(predicates ...predicate.Car) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			for _, p := range predicates {
+				p(s)
+			}
+		},
+	)
+}
+
+// Or groups list of predicates with the OR operator between them.
+func Or(predicates ...predicate.Car) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			for i, p := range predicates {
+				if i > 0 {
+					s.Or()
+				}
+				p(s)
+			}
+		},
+	)
+}
+
+// Not applies the not operator on the given predicate.
+func Not(p predicate.Car) predicate.Car {
+	return predicate.Car(
+		func(s *sql.Selector) {
+			p(s.Not())
+		},
+	)
+}

examples/start/ent/car_create.go

@@ -0,0 +1,125 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"time"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+)
+
+// CarCreate is the builder for creating a Car entity.
+type CarCreate struct {
+	config
+	model         *string
+	registered_at *time.Time
+	owner         map[int]struct{}
+}
+
+// SetModel sets the model field.
+func (cc *CarCreate) SetModel(s string) *CarCreate {
+	cc.model = &s
+	return cc
+}
+
+// SetRegisteredAt sets the registered_at field.
+func (cc *CarCreate) SetRegisteredAt(t time.Time) *CarCreate {
+	cc.registered_at = &t
+	return cc
+}
+
+// SetOwnerID sets the owner edge to User by id.
+func (cc *CarCreate) SetOwnerID(id int) *CarCreate {
+	if cc.owner == nil {
+		cc.owner = make(map[int]struct{})
+	}
+	cc.owner[id] = struct{}{}
+	return cc
+}
+
+// SetNillableOwnerID sets the owner edge to User by id if the given value is not nil.
+func (cc *CarCreate) SetNillableOwnerID(id *int) *CarCreate {
+	if id != nil {
+		cc = cc.SetOwnerID(*id)
+	}
+	return cc
+}
+
+// SetOwner sets the owner edge to User.
+func (cc *CarCreate) SetOwner(u *User) *CarCreate {
+	return cc.SetOwnerID(u.ID)
+}
+
+// Save creates the Car in the database.
+func (cc *CarCreate) Save(ctx context.Context) (*Car, error) {
+	if cc.model == nil {
+		return nil, errors.New("ent: missing required field \"model\"")
+	}
+	if cc.registered_at == nil {
+		return nil, errors.New("ent: missing required field \"registered_at\"")
+	}
+	if len(cc.owner) > 1 {
+		return nil, errors.New("ent: multiple assignments on a unique edge \"owner\"")
+	}
+	return cc.sqlSave(ctx)
+}
+
+// SaveX calls Save and panics if Save returns an error.
+func (cc *CarCreate) SaveX(ctx context.Context) *Car {
+	v, err := cc.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (cc *CarCreate) sqlSave(ctx context.Context) (*Car, error) {
+	var (
+		res sql.Result
+		c   = &Car{config: cc.config}
+	)
+	tx, err := cc.driver.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	builder := sql.Insert(car.Table).Default(cc.driver.Dialect())
+	if value := cc.model; value != nil {
+		builder.Set(car.FieldModel, *value)
+		c.Model = *value
+	}
+	if value := cc.registered_at; value != nil {
+		builder.Set(car.FieldRegisteredAt, *value)
+		c.RegisteredAt = *value
+	}
+	query, args := builder.Query()
+	if err := tx.Exec(ctx, query, args, &res); err != nil {
+		return nil, rollback(tx, err)
+	}
+	id, err := res.LastInsertId()
+	if err != nil {
+		return nil, rollback(tx, err)
+	}
+	c.ID = int(id)
+	if len(cc.owner) > 0 {
+		for eid := range cc.owner {
+			query, args := sql.Update(car.OwnerTable).
+				Set(car.OwnerColumn, eid).
+				Where(sql.EQ(car.FieldID, id)).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return nil, rollback(tx, err)
+			}
+		}
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return c, nil
+}

examples/start/ent/car_delete.go

@@ -0,0 +1,81 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+)
+
+// CarDelete is the builder for deleting a Car entity.
+type CarDelete struct {
+	config
+	predicates []predicate.Car
+}
+
+// Where adds a new predicate to the delete builder.
+func (cd *CarDelete) Where(ps ...predicate.Car) *CarDelete {
+	cd.predicates = append(cd.predicates, ps...)
+	return cd
+}
+
+// Exec executes the deletion query and returns how many vertices were deleted.
+func (cd *CarDelete) Exec(ctx context.Context) (int, error) {
+	return cd.sqlExec(ctx)
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (cd *CarDelete) ExecX(ctx context.Context) int {
+	n, err := cd.Exec(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+func (cd *CarDelete) sqlExec(ctx context.Context) (int, error) {
+	var res sql.Result
+	selector := sql.Select().From(sql.Table(car.Table))
+	for _, p := range cd.predicates {
+		p(selector)
+	}
+	query, args := sql.Delete(car.Table).FromSelect(selector).Query()
+	if err := cd.driver.Exec(ctx, query, args, &res); err != nil {
+		return 0, err
+	}
+	affected, err := res.RowsAffected()
+	if err != nil {
+		return 0, err
+	}
+	return int(affected), nil
+}
+
+// CarDeleteOne is the builder for deleting a single Car entity.
+type CarDeleteOne struct {
+	cd *CarDelete
+}
+
+// Exec executes the deletion query.
+func (cdo *CarDeleteOne) Exec(ctx context.Context) error {
+	n, err := cdo.cd.Exec(ctx)
+	switch {
+	case err != nil:
+		return err
+	case n == 0:
+		return &ErrNotFound{car.Label}
+	default:
+		return nil
+	}
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (cdo *CarDeleteOne) ExecX(ctx context.Context) {
+	cdo.cd.ExecX(ctx)
+}

examples/start/ent/car_query.go

@@ -0,0 +1,610 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// CarQuery is the builder for querying Car entities.
+type CarQuery struct {
+	config
+	limit      *int
+	offset     *int
+	order      []Order
+	unique     []string
+	predicates []predicate.Car
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Where adds a new predicate for the builder.
+func (cq *CarQuery) Where(ps ...predicate.Car) *CarQuery {
+	cq.predicates = append(cq.predicates, ps...)
+	return cq
+}
+
+// Limit adds a limit step to the query.
+func (cq *CarQuery) Limit(limit int) *CarQuery {
+	cq.limit = &limit
+	return cq
+}
+
+// Offset adds an offset step to the query.
+func (cq *CarQuery) Offset(offset int) *CarQuery {
+	cq.offset = &offset
+	return cq
+}
+
+// Order adds an order step to the query.
+func (cq *CarQuery) Order(o ...Order) *CarQuery {
+	cq.order = append(cq.order, o...)
+	return cq
+}
+
+// QueryOwner chains the current query on the owner edge.
+func (cq *CarQuery) QueryOwner() *UserQuery {
+	query := &UserQuery{config: cq.config}
+	t1 := sql.Table(user.Table)
+	t2 := cq.sqlQuery()
+	t2.Select(t2.C(car.OwnerColumn))
+	query.sql = sql.Select(t1.Columns(user.Columns...)...).
+		From(t1).
+		Join(t2).
+		On(t1.C(user.FieldID), t2.C(car.OwnerColumn))
+	return query
+}
+
+// First returns the first Car entity in the query. Returns *ErrNotFound when no car was found.
+func (cq *CarQuery) First(ctx context.Context) (*Car, error) {
+	cs, err := cq.Limit(1).All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if len(cs) == 0 {
+		return nil, &ErrNotFound{car.Label}
+	}
+	return cs[0], nil
+}
+
+// FirstX is like First, but panics if an error occurs.
+func (cq *CarQuery) FirstX(ctx context.Context) *Car {
+	c, err := cq.First(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return c
+}
+
+// FirstID returns the first Car id in the query. Returns *ErrNotFound when no id was found.
+func (cq *CarQuery) FirstID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = cq.Limit(1).IDs(ctx); err != nil {
+		return
+	}
+	if len(ids) == 0 {
+		err = &ErrNotFound{car.Label}
+		return
+	}
+	return ids[0], nil
+}
+
+// FirstXID is like FirstID, but panics if an error occurs.
+func (cq *CarQuery) FirstXID(ctx context.Context) int {
+	id, err := cq.FirstID(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return id
+}
+
+// Only returns the only Car entity in the query, returns an error if not exactly one entity was returned.
+func (cq *CarQuery) Only(ctx context.Context) (*Car, error) {
+	cs, err := cq.Limit(2).All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	switch len(cs) {
+	case 1:
+		return cs[0], nil
+	case 0:
+		return nil, &ErrNotFound{car.Label}
+	default:
+		return nil, &ErrNotSingular{car.Label}
+	}
+}
+
+// OnlyX is like Only, but panics if an error occurs.
+func (cq *CarQuery) OnlyX(ctx context.Context) *Car {
+	c, err := cq.Only(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return c
+}
+
+// OnlyID returns the only Car id in the query, returns an error if not exactly one id was returned.
+func (cq *CarQuery) OnlyID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = cq.Limit(2).IDs(ctx); err != nil {
+		return
+	}
+	switch len(ids) {
+	case 1:
+		id = ids[0]
+	case 0:
+		err = &ErrNotFound{car.Label}
+	default:
+		err = &ErrNotSingular{car.Label}
+	}
+	return
+}
+
+// OnlyXID is like OnlyID, but panics if an error occurs.
+func (cq *CarQuery) OnlyXID(ctx context.Context) int {
+	id, err := cq.OnlyID(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+// All executes the query and returns a list of Cars.
+func (cq *CarQuery) All(ctx context.Context) ([]*Car, error) {
+	return cq.sqlAll(ctx)
+}
+
+// AllX is like All, but panics if an error occurs.
+func (cq *CarQuery) AllX(ctx context.Context) []*Car {
+	cs, err := cq.All(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return cs
+}
+
+// IDs executes the query and returns a list of Car ids.
+func (cq *CarQuery) IDs(ctx context.Context) ([]int, error) {
+	return cq.sqlIDs(ctx)
+}
+
+// IDsX is like IDs, but panics if an error occurs.
+func (cq *CarQuery) IDsX(ctx context.Context) []int {
+	ids, err := cq.IDs(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return ids
+}
+
+// Count returns the count of the given query.
+func (cq *CarQuery) Count(ctx context.Context) (int, error) {
+	return cq.sqlCount(ctx)
+}
+
+// CountX is like Count, but panics if an error occurs.
+func (cq *CarQuery) CountX(ctx context.Context) int {
+	count, err := cq.Count(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return count
+}
+
+// Exist returns true if the query has elements in the graph.
+func (cq *CarQuery) Exist(ctx context.Context) (bool, error) {
+	return cq.sqlExist(ctx)
+}
+
+// ExistX is like Exist, but panics if an error occurs.
+func (cq *CarQuery) ExistX(ctx context.Context) bool {
+	exist, err := cq.Exist(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return exist
+}
+
+// Clone returns a duplicate of the query builder, including all associated steps. It can be
+// used to prepare common query builders and use them differently after the clone is made.
+func (cq *CarQuery) Clone() *CarQuery {
+	return &CarQuery{
+		config:     cq.config,
+		limit:      cq.limit,
+		offset:     cq.offset,
+		order:      append([]Order{}, cq.order...),
+		unique:     append([]string{}, cq.unique...),
+		predicates: append([]predicate.Car{}, cq.predicates...),
+		// clone intermediate queries.
+		sql: cq.sql.Clone(),
+	}
+}
+
+// GroupBy used to group vertices by one or more fields/columns.
+// It is often used with aggregate functions, like: count, max, mean, min, sum.
+//
+// Example:
+//
+//	var v []struct {
+//		Model string `json:"model,omitempty"`
+//		Count int `json:"count,omitempty"`
+//	}
+//
+//	client.Car.Query().
+//		GroupBy(car.FieldModel).
+//		Aggregate(ent.Count()).
+//		Scan(ctx, &v)
+//
+func (cq *CarQuery) GroupBy(field string, fields ...string) *CarGroupBy {
+	group := &CarGroupBy{config: cq.config}
+	group.fields = append([]string{field}, fields...)
+	group.sql = cq.sqlQuery()
+	return group
+}
+
+// Select one or more fields from the given query.
+//
+// Example:
+//
+//	var v []struct {
+//		Model string `json:"model,omitempty"`
+//	}
+//
+//	client.Car.Query().
+//		Select(car.FieldModel).
+//		Scan(ctx, &v)
+//
+func (cq *CarQuery) Select(field string, fields ...string) *CarSelect {
+	selector := &CarSelect{config: cq.config}
+	selector.fields = append([]string{field}, fields...)
+	selector.sql = cq.sqlQuery()
+	return selector
+}
+
+func (cq *CarQuery) sqlAll(ctx context.Context) ([]*Car, error) {
+	rows := &sql.Rows{}
+	selector := cq.sqlQuery()
+	if unique := cq.unique; len(unique) == 0 {
+		selector.Distinct()
+	}
+	query, args := selector.Query()
+	if err := cq.driver.Query(ctx, query, args, rows); err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var cs Cars
+	if err := cs.FromRows(rows); err != nil {
+		return nil, err
+	}
+	cs.config(cq.config)
+	return cs, nil
+}
+
+func (cq *CarQuery) sqlCount(ctx context.Context) (int, error) {
+	rows := &sql.Rows{}
+	selector := cq.sqlQuery()
+	unique := []string{car.FieldID}
+	if len(cq.unique) > 0 {
+		unique = cq.unique
+	}
+	selector.Count(sql.Distinct(selector.Columns(unique...)...))
+	query, args := selector.Query()
+	if err := cq.driver.Query(ctx, query, args, rows); err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+	if !rows.Next() {
+		return 0, errors.New("ent: no rows found")
+	}
+	var n int
+	if err := rows.Scan(&n); err != nil {
+		return 0, fmt.Errorf("ent: failed reading count: %v", err)
+	}
+	return n, nil
+}
+
+func (cq *CarQuery) sqlExist(ctx context.Context) (bool, error) {
+	n, err := cq.sqlCount(ctx)
+	if err != nil {
+		return false, fmt.Errorf("ent: check existence: %v", err)
+	}
+	return n > 0, nil
+}
+
+func (cq *CarQuery) sqlIDs(ctx context.Context) ([]int, error) {
+	vs, err := cq.sqlAll(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var ids []int
+	for _, v := range vs {
+		ids = append(ids, v.ID)
+	}
+	return ids, nil
+}
+
+func (cq *CarQuery) sqlQuery() *sql.Selector {
+	t1 := sql.Table(car.Table)
+	selector := sql.Select(t1.Columns(car.Columns...)...).From(t1)
+	if cq.sql != nil {
+		selector = cq.sql
+		selector.Select(selector.Columns(car.Columns...)...)
+	}
+	for _, p := range cq.predicates {
+		p(selector)
+	}
+	for _, p := range cq.order {
+		p(selector)
+	}
+	if offset := cq.offset; offset != nil {
+		// limit is mandatory for offset clause. We start
+		// with default value, and override it below if needed.
+		selector.Offset(*offset).Limit(math.MaxInt64)
+	}
+	if limit := cq.limit; limit != nil {
+		selector.Limit(*limit)
+	}
+	return selector
+}
+
+// CarGroupBy is the builder for group-by Car entities.
+type CarGroupBy struct {
+	config
+	fields []string
+	fns    []Aggregate
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Aggregate adds the given aggregation functions to the group-by query.
+func (cgb *CarGroupBy) Aggregate(fns ...Aggregate) *CarGroupBy {
+	cgb.fns = append(cgb.fns, fns...)
+	return cgb
+}
+
+// Scan applies the group-by query and scan the result into the given value.
+func (cgb *CarGroupBy) Scan(ctx context.Context, v interface{}) error {
+	return cgb.sqlScan(ctx, v)
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (cgb *CarGroupBy) ScanX(ctx context.Context, v interface{}) {
+	if err := cgb.Scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from group-by. It is only allowed when querying group-by with one field.
+func (cgb *CarGroupBy) Strings(ctx context.Context) ([]string, error) {
+	if len(cgb.fields) > 1 {
+		return nil, errors.New("ent: CarGroupBy.Strings is not achievable when grouping more than 1 field")
+	}
+	var v []string
+	if err := cgb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (cgb *CarGroupBy) StringsX(ctx context.Context) []string {
+	v, err := cgb.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from group-by. It is only allowed when querying group-by with one field.
+func (cgb *CarGroupBy) Ints(ctx context.Context) ([]int, error) {
+	if len(cgb.fields) > 1 {
+		return nil, errors.New("ent: CarGroupBy.Ints is not achievable when grouping more than 1 field")
+	}
+	var v []int
+	if err := cgb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (cgb *CarGroupBy) IntsX(ctx context.Context) []int {
+	v, err := cgb.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from group-by. It is only allowed when querying group-by with one field.
+func (cgb *CarGroupBy) Float64s(ctx context.Context) ([]float64, error) {
+	if len(cgb.fields) > 1 {
+		return nil, errors.New("ent: CarGroupBy.Float64s is not achievable when grouping more than 1 field")
+	}
+	var v []float64
+	if err := cgb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (cgb *CarGroupBy) Float64sX(ctx context.Context) []float64 {
+	v, err := cgb.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from group-by. It is only allowed when querying group-by with one field.
+func (cgb *CarGroupBy) Bools(ctx context.Context) ([]bool, error) {
+	if len(cgb.fields) > 1 {
+		return nil, errors.New("ent: CarGroupBy.Bools is not achievable when grouping more than 1 field")
+	}
+	var v []bool
+	if err := cgb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (cgb *CarGroupBy) BoolsX(ctx context.Context) []bool {
+	v, err := cgb.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (cgb *CarGroupBy) sqlScan(ctx context.Context, v interface{}) error {
+	rows := &sql.Rows{}
+	query, args := cgb.sqlQuery().Query()
+	if err := cgb.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+func (cgb *CarGroupBy) sqlQuery() *sql.Selector {
+	selector := cgb.sql
+	columns := make([]string, 0, len(cgb.fields)+len(cgb.fns))
+	columns = append(columns, cgb.fields...)
+	for _, fn := range cgb.fns {
+		columns = append(columns, fn.SQL(selector))
+	}
+	return selector.Select(columns...).GroupBy(cgb.fields...)
+}
+
+// CarSelect is the builder for select fields of Car entities.
+type CarSelect struct {
+	config
+	fields []string
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Scan applies the selector query and scan the result into the given value.
+func (cs *CarSelect) Scan(ctx context.Context, v interface{}) error {
+	return cs.sqlScan(ctx, v)
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (cs *CarSelect) ScanX(ctx context.Context, v interface{}) {
+	if err := cs.Scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from selector. It is only allowed when selecting one field.
+func (cs *CarSelect) Strings(ctx context.Context) ([]string, error) {
+	if len(cs.fields) > 1 {
+		return nil, errors.New("ent: CarSelect.Strings is not achievable when selecting more than 1 field")
+	}
+	var v []string
+	if err := cs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (cs *CarSelect) StringsX(ctx context.Context) []string {
+	v, err := cs.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from selector. It is only allowed when selecting one field.
+func (cs *CarSelect) Ints(ctx context.Context) ([]int, error) {
+	if len(cs.fields) > 1 {
+		return nil, errors.New("ent: CarSelect.Ints is not achievable when selecting more than 1 field")
+	}
+	var v []int
+	if err := cs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (cs *CarSelect) IntsX(ctx context.Context) []int {
+	v, err := cs.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from selector. It is only allowed when selecting one field.
+func (cs *CarSelect) Float64s(ctx context.Context) ([]float64, error) {
+	if len(cs.fields) > 1 {
+		return nil, errors.New("ent: CarSelect.Float64s is not achievable when selecting more than 1 field")
+	}
+	var v []float64
+	if err := cs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (cs *CarSelect) Float64sX(ctx context.Context) []float64 {
+	v, err := cs.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from selector. It is only allowed when selecting one field.
+func (cs *CarSelect) Bools(ctx context.Context) ([]bool, error) {
+	if len(cs.fields) > 1 {
+		return nil, errors.New("ent: CarSelect.Bools is not achievable when selecting more than 1 field")
+	}
+	var v []bool
+	if err := cs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (cs *CarSelect) BoolsX(ctx context.Context) []bool {
+	v, err := cs.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (cs *CarSelect) sqlScan(ctx context.Context, v interface{}) error {
+	rows := &sql.Rows{}
+	query, args := cs.sqlQuery().Query()
+	if err := cs.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+func (cs *CarSelect) sqlQuery() sql.Querier {
+	view := "car_view"
+	return sql.Select(cs.fields...).From(cs.sql.As(view))
+}

examples/start/ent/car_update.go

@@ -0,0 +1,328 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// CarUpdate is the builder for updating Car entities.
+type CarUpdate struct {
+	config
+	model         *string
+	registered_at *time.Time
+	owner         map[int]struct{}
+	clearedOwner  bool
+	predicates    []predicate.Car
+}
+
+// Where adds a new predicate for the builder.
+func (cu *CarUpdate) Where(ps ...predicate.Car) *CarUpdate {
+	cu.predicates = append(cu.predicates, ps...)
+	return cu
+}
+
+// SetModel sets the model field.
+func (cu *CarUpdate) SetModel(s string) *CarUpdate {
+	cu.model = &s
+	return cu
+}
+
+// SetRegisteredAt sets the registered_at field.
+func (cu *CarUpdate) SetRegisteredAt(t time.Time) *CarUpdate {
+	cu.registered_at = &t
+	return cu
+}
+
+// SetOwnerID sets the owner edge to User by id.
+func (cu *CarUpdate) SetOwnerID(id int) *CarUpdate {
+	if cu.owner == nil {
+		cu.owner = make(map[int]struct{})
+	}
+	cu.owner[id] = struct{}{}
+	return cu
+}
+
+// SetNillableOwnerID sets the owner edge to User by id if the given value is not nil.
+func (cu *CarUpdate) SetNillableOwnerID(id *int) *CarUpdate {
+	if id != nil {
+		cu = cu.SetOwnerID(*id)
+	}
+	return cu
+}
+
+// SetOwner sets the owner edge to User.
+func (cu *CarUpdate) SetOwner(u *User) *CarUpdate {
+	return cu.SetOwnerID(u.ID)
+}
+
+// ClearOwner clears the owner edge to User.
+func (cu *CarUpdate) ClearOwner() *CarUpdate {
+	cu.clearedOwner = true
+	return cu
+}
+
+// Save executes the query and returns the number of rows/vertices matched by this operation.
+func (cu *CarUpdate) Save(ctx context.Context) (int, error) {
+	if len(cu.owner) > 1 {
+		return 0, errors.New("ent: multiple assignments on a unique edge \"owner\"")
+	}
+	return cu.sqlSave(ctx)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (cu *CarUpdate) SaveX(ctx context.Context) int {
+	affected, err := cu.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return affected
+}
+
+// Exec executes the query.
+func (cu *CarUpdate) Exec(ctx context.Context) error {
+	_, err := cu.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (cu *CarUpdate) ExecX(ctx context.Context) {
+	if err := cu.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (cu *CarUpdate) sqlSave(ctx context.Context) (n int, err error) {
+	selector := sql.Select(car.FieldID).From(sql.Table(car.Table))
+	for _, p := range cu.predicates {
+		p(selector)
+	}
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err = cu.driver.Query(ctx, query, args, rows); err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+	var ids []int
+	for rows.Next() {
+		var id int
+		if err := rows.Scan(&id); err != nil {
+			return 0, fmt.Errorf("ent: failed reading id: %v", err)
+		}
+		ids = append(ids, id)
+	}
+	if len(ids) == 0 {
+		return 0, nil
+	}
+
+	tx, err := cu.driver.Tx(ctx)
+	if err != nil {
+		return 0, err
+	}
+	var (
+		res     sql.Result
+		builder = sql.Update(car.Table).Where(sql.InInts(car.FieldID, ids...))
+	)
+	if value := cu.model; value != nil {
+		builder.Set(car.FieldModel, *value)
+	}
+	if value := cu.registered_at; value != nil {
+		builder.Set(car.FieldRegisteredAt, *value)
+	}
+	if !builder.Empty() {
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if cu.clearedOwner {
+		query, args := sql.Update(car.OwnerTable).
+			SetNull(car.OwnerColumn).
+			Where(sql.InInts(user.FieldID, ids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if len(cu.owner) > 0 {
+		for eid := range cu.owner {
+			query, args := sql.Update(car.OwnerTable).
+				Set(car.OwnerColumn, eid).
+				Where(sql.InInts(car.FieldID, ids...)).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return 0, rollback(tx, err)
+			}
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return 0, err
+	}
+	return len(ids), nil
+}
+
+// CarUpdateOne is the builder for updating a single Car entity.
+type CarUpdateOne struct {
+	config
+	id            int
+	model         *string
+	registered_at *time.Time
+	owner         map[int]struct{}
+	clearedOwner  bool
+}
+
+// SetModel sets the model field.
+func (cuo *CarUpdateOne) SetModel(s string) *CarUpdateOne {
+	cuo.model = &s
+	return cuo
+}
+
+// SetRegisteredAt sets the registered_at field.
+func (cuo *CarUpdateOne) SetRegisteredAt(t time.Time) *CarUpdateOne {
+	cuo.registered_at = &t
+	return cuo
+}
+
+// SetOwnerID sets the owner edge to User by id.
+func (cuo *CarUpdateOne) SetOwnerID(id int) *CarUpdateOne {
+	if cuo.owner == nil {
+		cuo.owner = make(map[int]struct{})
+	}
+	cuo.owner[id] = struct{}{}
+	return cuo
+}
+
+// SetNillableOwnerID sets the owner edge to User by id if the given value is not nil.
+func (cuo *CarUpdateOne) SetNillableOwnerID(id *int) *CarUpdateOne {
+	if id != nil {
+		cuo = cuo.SetOwnerID(*id)
+	}
+	return cuo
+}
+
+// SetOwner sets the owner edge to User.
+func (cuo *CarUpdateOne) SetOwner(u *User) *CarUpdateOne {
+	return cuo.SetOwnerID(u.ID)
+}
+
+// ClearOwner clears the owner edge to User.
+func (cuo *CarUpdateOne) ClearOwner() *CarUpdateOne {
+	cuo.clearedOwner = true
+	return cuo
+}
+
+// Save executes the query and returns the updated entity.
+func (cuo *CarUpdateOne) Save(ctx context.Context) (*Car, error) {
+	if len(cuo.owner) > 1 {
+		return nil, errors.New("ent: multiple assignments on a unique edge \"owner\"")
+	}
+	return cuo.sqlSave(ctx)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (cuo *CarUpdateOne) SaveX(ctx context.Context) *Car {
+	c, err := cuo.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return c
+}
+
+// Exec executes the query on the entity.
+func (cuo *CarUpdateOne) Exec(ctx context.Context) error {
+	_, err := cuo.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (cuo *CarUpdateOne) ExecX(ctx context.Context) {
+	if err := cuo.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (cuo *CarUpdateOne) sqlSave(ctx context.Context) (c *Car, err error) {
+	selector := sql.Select(car.Columns...).From(sql.Table(car.Table))
+	car.ID(cuo.id)(selector)
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err = cuo.driver.Query(ctx, query, args, rows); err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []int
+	for rows.Next() {
+		var id int
+		c = &Car{config: cuo.config}
+		if err := c.FromRows(rows); err != nil {
+			return nil, fmt.Errorf("ent: failed scanning row into Car: %v", err)
+		}
+		id = c.ID
+		ids = append(ids, id)
+	}
+	switch n := len(ids); {
+	case n == 0:
+		return nil, fmt.Errorf("ent: Car not found with id: %v", cuo.id)
+	case n > 1:
+		return nil, fmt.Errorf("ent: more than one Car with the same id: %v", cuo.id)
+	}
+
+	tx, err := cuo.driver.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var (
+		res     sql.Result
+		builder = sql.Update(car.Table).Where(sql.InInts(car.FieldID, ids...))
+	)
+	if value := cuo.model; value != nil {
+		builder.Set(car.FieldModel, *value)
+		c.Model = *value
+	}
+	if value := cuo.registered_at; value != nil {
+		builder.Set(car.FieldRegisteredAt, *value)
+		c.RegisteredAt = *value
+	}
+	if !builder.Empty() {
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if cuo.clearedOwner {
+		query, args := sql.Update(car.OwnerTable).
+			SetNull(car.OwnerColumn).
+			Where(sql.InInts(user.FieldID, ids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if len(cuo.owner) > 0 {
+		for eid := range cuo.owner {
+			query, args := sql.Update(car.OwnerTable).
+				Set(car.OwnerColumn, eid).
+				Where(sql.InInts(car.FieldID, ids...)).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return nil, rollback(tx, err)
+			}
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return nil, err
+	}
+	return c, nil
+}

examples/start/ent/client.go

@@ -0,0 +1,364 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/facebookincubator/ent/examples/start/ent/migrate"
+
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+
+	"github.com/facebookincubator/ent/dialect"
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// Client is the client that holds all ent builders.
+type Client struct {
+	config
+	// Schema is the client for creating, migrating and dropping schema.
+	Schema *migrate.Schema
+	// Car is the client for interacting with the Car builders.
+	Car *CarClient
+	// Group is the client for interacting with the Group builders.
+	Group *GroupClient
+	// User is the client for interacting with the User builders.
+	User *UserClient
+}
+
+// NewClient creates a new client configured with the given options.
+func NewClient(opts ...Option) *Client {
+	c := config{log: log.Println}
+	c.options(opts...)
+	return &Client{
+		config: c,
+		Schema: migrate.NewSchema(c.driver),
+		Car:    NewCarClient(c),
+		Group:  NewGroupClient(c),
+		User:   NewUserClient(c),
+	}
+}
+
+// Open opens a connection to the database specified by the driver name and a
+// driver-specific data source name, and returns a new client attached to it.
+// Optional parameters can be added for configuring the client.
+func Open(driverName, dataSourceName string, options ...Option) (*Client, error) {
+	switch driverName {
+	case dialect.MySQL, dialect.SQLite:
+		drv, err := sql.Open(driverName, dataSourceName)
+		if err != nil {
+			return nil, err
+		}
+		return NewClient(append(options, Driver(drv))...), nil
+
+	default:
+		return nil, fmt.Errorf("unsupported driver: %q", driverName)
+	}
+}
+
+// Tx returns a new transactional client.
+func (c *Client) Tx(ctx context.Context) (*Tx, error) {
+	if _, ok := c.driver.(*txDriver); ok {
+		return nil, fmt.Errorf("ent: cannot start a transaction within a transaction")
+	}
+	tx, err := newTx(ctx, c.driver)
+	if err != nil {
+		return nil, fmt.Errorf("ent: starting a transaction: %v", err)
+	}
+	cfg := config{driver: tx, log: c.log, debug: c.debug}
+	return &Tx{
+		config: cfg,
+		Car:    NewCarClient(cfg),
+		Group:  NewGroupClient(cfg),
+		User:   NewUserClient(cfg),
+	}, nil
+}
+
+// Debug returns a new debug-client. It's used to get verbose logging on specific operations.
+//
+//	client.Debug().
+//		Car.
+//		Query().
+//		Count(ctx)
+//
+func (c *Client) Debug() *Client {
+	if c.debug {
+		return c
+	}
+	cfg := config{driver: dialect.Debug(c.driver, c.log), log: c.log, debug: true}
+	return &Client{
+		config: cfg,
+		Schema: migrate.NewSchema(cfg.driver),
+		Car:    NewCarClient(cfg),
+		Group:  NewGroupClient(cfg),
+		User:   NewUserClient(cfg),
+	}
+}
+
+// Close closes the database connection and prevents new queries from starting.
+func (c *Client) Close() error {
+	return c.driver.Close()
+}
+
+// CarClient is a client for the Car schema.
+type CarClient struct {
+	config
+}
+
+// NewCarClient returns a client for the Car from the given config.
+func NewCarClient(c config) *CarClient {
+	return &CarClient{config: c}
+}
+
+// Create returns a create builder for Car.
+func (c *CarClient) Create() *CarCreate {
+	return &CarCreate{config: c.config}
+}
+
+// Update returns an update builder for Car.
+func (c *CarClient) Update() *CarUpdate {
+	return &CarUpdate{config: c.config}
+}
+
+// UpdateOne returns an update builder for the given entity.
+func (c *CarClient) UpdateOne(ca *Car) *CarUpdateOne {
+	return c.UpdateOneID(ca.ID)
+}
+
+// UpdateOneID returns an update builder for the given id.
+func (c *CarClient) UpdateOneID(id int) *CarUpdateOne {
+	return &CarUpdateOne{config: c.config, id: id}
+}
+
+// Delete returns a delete builder for Car.
+func (c *CarClient) Delete() *CarDelete {
+	return &CarDelete{config: c.config}
+}
+
+// DeleteOne returns a delete builder for the given entity.
+func (c *CarClient) DeleteOne(ca *Car) *CarDeleteOne {
+	return c.DeleteOneID(ca.ID)
+}
+
+// DeleteOneID returns a delete builder for the given id.
+func (c *CarClient) DeleteOneID(id int) *CarDeleteOne {
+	return &CarDeleteOne{c.Delete().Where(car.ID(id))}
+}
+
+// Create returns a query builder for Car.
+func (c *CarClient) Query() *CarQuery {
+	return &CarQuery{config: c.config}
+}
+
+// Get returns a Car entity by its id.
+func (c *CarClient) Get(ctx context.Context, id int) (*Car, error) {
+	return c.Query().Where(car.ID(id)).Only(ctx)
+}
+
+// GetX is like Get, but panics if an error occurs.
+func (c *CarClient) GetX(ctx context.Context, id int) *Car {
+	ca, err := c.Get(ctx, id)
+	if err != nil {
+		panic(err)
+	}
+	return ca
+}
+
+// QueryOwner queries the owner edge of a Car.
+func (c *CarClient) QueryOwner(ca *Car) *UserQuery {
+	query := &UserQuery{config: c.config}
+	id := ca.ID
+	t1 := sql.Table(user.Table)
+	t2 := sql.Select(car.OwnerColumn).
+		From(sql.Table(car.OwnerTable)).
+		Where(sql.EQ(car.FieldID, id))
+	query.sql = sql.Select().From(t1).Join(t2).On(t1.C(user.FieldID), t2.C(car.OwnerColumn))
+
+	return query
+}
+
+// GroupClient is a client for the Group schema.
+type GroupClient struct {
+	config
+}
+
+// NewGroupClient returns a client for the Group from the given config.
+func NewGroupClient(c config) *GroupClient {
+	return &GroupClient{config: c}
+}
+
+// Create returns a create builder for Group.
+func (c *GroupClient) Create() *GroupCreate {
+	return &GroupCreate{config: c.config}
+}
+
+// Update returns an update builder for Group.
+func (c *GroupClient) Update() *GroupUpdate {
+	return &GroupUpdate{config: c.config}
+}
+
+// UpdateOne returns an update builder for the given entity.
+func (c *GroupClient) UpdateOne(gr *Group) *GroupUpdateOne {
+	return c.UpdateOneID(gr.ID)
+}
+
+// UpdateOneID returns an update builder for the given id.
+func (c *GroupClient) UpdateOneID(id int) *GroupUpdateOne {
+	return &GroupUpdateOne{config: c.config, id: id}
+}
+
+// Delete returns a delete builder for Group.
+func (c *GroupClient) Delete() *GroupDelete {
+	return &GroupDelete{config: c.config}
+}
+
+// DeleteOne returns a delete builder for the given entity.
+func (c *GroupClient) DeleteOne(gr *Group) *GroupDeleteOne {
+	return c.DeleteOneID(gr.ID)
+}
+
+// DeleteOneID returns a delete builder for the given id.
+func (c *GroupClient) DeleteOneID(id int) *GroupDeleteOne {
+	return &GroupDeleteOne{c.Delete().Where(group.ID(id))}
+}
+
+// Create returns a query builder for Group.
+func (c *GroupClient) Query() *GroupQuery {
+	return &GroupQuery{config: c.config}
+}
+
+// Get returns a Group entity by its id.
+func (c *GroupClient) Get(ctx context.Context, id int) (*Group, error) {
+	return c.Query().Where(group.ID(id)).Only(ctx)
+}
+
+// GetX is like Get, but panics if an error occurs.
+func (c *GroupClient) GetX(ctx context.Context, id int) *Group {
+	gr, err := c.Get(ctx, id)
+	if err != nil {
+		panic(err)
+	}
+	return gr
+}
+
+// QueryUsers queries the users edge of a Group.
+func (c *GroupClient) QueryUsers(gr *Group) *UserQuery {
+	query := &UserQuery{config: c.config}
+	id := gr.ID
+	t1 := sql.Table(user.Table)
+	t2 := sql.Table(group.Table)
+	t3 := sql.Table(group.UsersTable)
+	t4 := sql.Select(t3.C(group.UsersPrimaryKey[1])).
+		From(t3).
+		Join(t2).
+		On(t3.C(group.UsersPrimaryKey[0]), t2.C(group.FieldID)).
+		Where(sql.EQ(t2.C(group.FieldID), id))
+	query.sql = sql.Select().
+		From(t1).
+		Join(t4).
+		On(t1.C(user.FieldID), t4.C(group.UsersPrimaryKey[1]))
+
+	return query
+}
+
+// UserClient is a client for the User schema.
+type UserClient struct {
+	config
+}
+
+// NewUserClient returns a client for the User from the given config.
+func NewUserClient(c config) *UserClient {
+	return &UserClient{config: c}
+}
+
+// Create returns a create builder for User.
+func (c *UserClient) Create() *UserCreate {
+	return &UserCreate{config: c.config}
+}
+
+// Update returns an update builder for User.
+func (c *UserClient) Update() *UserUpdate {
+	return &UserUpdate{config: c.config}
+}
+
+// UpdateOne returns an update builder for the given entity.
+func (c *UserClient) UpdateOne(u *User) *UserUpdateOne {
+	return c.UpdateOneID(u.ID)
+}
+
+// UpdateOneID returns an update builder for the given id.
+func (c *UserClient) UpdateOneID(id int) *UserUpdateOne {
+	return &UserUpdateOne{config: c.config, id: id}
+}
+
+// Delete returns a delete builder for User.
+func (c *UserClient) Delete() *UserDelete {
+	return &UserDelete{config: c.config}
+}
+
+// DeleteOne returns a delete builder for the given entity.
+func (c *UserClient) DeleteOne(u *User) *UserDeleteOne {
+	return c.DeleteOneID(u.ID)
+}
+
+// DeleteOneID returns a delete builder for the given id.
+func (c *UserClient) DeleteOneID(id int) *UserDeleteOne {
+	return &UserDeleteOne{c.Delete().Where(user.ID(id))}
+}
+
+// Create returns a query builder for User.
+func (c *UserClient) Query() *UserQuery {
+	return &UserQuery{config: c.config}
+}
+
+// Get returns a User entity by its id.
+func (c *UserClient) Get(ctx context.Context, id int) (*User, error) {
+	return c.Query().Where(user.ID(id)).Only(ctx)
+}
+
+// GetX is like Get, but panics if an error occurs.
+func (c *UserClient) GetX(ctx context.Context, id int) *User {
+	u, err := c.Get(ctx, id)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}
+
+// QueryCars queries the cars edge of a User.
+func (c *UserClient) QueryCars(u *User) *CarQuery {
+	query := &CarQuery{config: c.config}
+	id := u.ID
+	query.sql = sql.Select().From(sql.Table(car.Table)).
+		Where(sql.EQ(user.CarsColumn, id))
+
+	return query
+}
+
+// QueryGroups queries the groups edge of a User.
+func (c *UserClient) QueryGroups(u *User) *GroupQuery {
+	query := &GroupQuery{config: c.config}
+	id := u.ID
+	t1 := sql.Table(group.Table)
+	t2 := sql.Table(user.Table)
+	t3 := sql.Table(user.GroupsTable)
+	t4 := sql.Select(t3.C(user.GroupsPrimaryKey[0])).
+		From(t3).
+		Join(t2).
+		On(t3.C(user.GroupsPrimaryKey[1]), t2.C(user.FieldID)).
+		Where(sql.EQ(t2.C(user.FieldID), id))
+	query.sql = sql.Select().
+		From(t1).
+		Join(t4).
+		On(t1.C(group.FieldID), t4.C(user.GroupsPrimaryKey[0]))
+
+	return query
+}

examples/start/ent/config.go

@@ -0,0 +1,55 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"github.com/facebookincubator/ent/dialect"
+)
+
+// Option function to configure the client.
+type Option func(*config)
+
+// Config is the configuration for the client and its builder.
+type config struct {
+	// driver used for executing database requests.
+	driver dialect.Driver
+	// debug enable a debug logging.
+	debug bool
+	// log used for logging on debug mode.
+	log func(...interface{})
+}
+
+// Options applies the options on the config object.
+func (c *config) options(opts ...Option) {
+	for _, opt := range opts {
+		opt(c)
+	}
+	if c.debug {
+		c.driver = dialect.Debug(c.driver, c.log)
+	}
+}
+
+// Debug enables debug logging on the ent.Driver.
+func Debug() Option {
+	return func(c *config) {
+		c.debug = true
+	}
+}
+
+// Log sets the logging function for debug mode.
+func Log(fn func(...interface{})) Option {
+	return func(c *config) {
+		c.log = fn
+	}
+}
+
+// Driver configures the client driver.
+func Driver(driver dialect.Driver) Option {
+	return func(c *config) {
+		c.driver = driver
+	}
+}

examples/start/ent/context.go

@@ -0,0 +1,24 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+)
+
+type contextKey struct{}
+
+// FromContext returns the Client stored in a context, or nil if there isn't one.
+func FromContext(ctx context.Context) *Client {
+	c, _ := ctx.Value(contextKey{}).(*Client)
+	return c
+}
+
+// NewContext returns a new context with the given Client attached.
+func NewContext(parent context.Context, c *Client) context.Context {
+	return context.WithValue(parent, contextKey{}, c)
+}

examples/start/ent/ent.go

@@ -0,0 +1,196 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/facebookincubator/ent/dialect"
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// Order applies an ordering on either graph traversal or sql selector.
+type Order func(*sql.Selector)
+
+// Asc applies the given fields in ASC order.
+func Asc(fields ...string) Order {
+	return Order(
+		func(s *sql.Selector) {
+			for _, f := range fields {
+				s.OrderBy(sql.Asc(f))
+			}
+		},
+	)
+}
+
+// Desc applies the given fields in DESC order.
+func Desc(fields ...string) Order {
+	return Order(
+		func(s *sql.Selector) {
+			for _, f := range fields {
+				s.OrderBy(sql.Desc(f))
+			}
+		},
+	)
+}
+
+// Aggregate applies an aggregation step on the group-by traversal/selector.
+type Aggregate struct {
+	// SQL the column wrapped with the aggregation function.
+	SQL func(*sql.Selector) string
+}
+
+// As is a pseudo aggregation function for renaming another other functions with custom names. For example:
+//
+//	GroupBy(field1, field2).
+//	Aggregate(ent.As(ent.Sum(field1), "sum_field1"), (ent.As(ent.Sum(field2), "sum_field2")).
+//	Scan(ctx, &v)
+//
+func As(fn Aggregate, end string) Aggregate {
+	return Aggregate{
+		SQL: func(s *sql.Selector) string {
+			return sql.As(fn.SQL(s), end)
+		},
+	}
+}
+
+// Count applies the "count" aggregation function on each group.
+func Count() Aggregate {
+	return Aggregate{
+		SQL: func(s *sql.Selector) string {
+			return sql.Count("*")
+		},
+	}
+}
+
+// Max applies the "max" aggregation function on the given field of each group.
+func Max(field string) Aggregate {
+	return Aggregate{
+		SQL: func(s *sql.Selector) string {
+			return sql.Max(s.C(field))
+		},
+	}
+}
+
+// Mean applies the "mean" aggregation function on the given field of each group.
+func Mean(field string) Aggregate {
+	return Aggregate{
+		SQL: func(s *sql.Selector) string {
+			return sql.Avg(s.C(field))
+		},
+	}
+}
+
+// Min applies the "min" aggregation function on the given field of each group.
+func Min(field string) Aggregate {
+	return Aggregate{
+		SQL: func(s *sql.Selector) string {
+			return sql.Min(s.C(field))
+		},
+	}
+}
+
+// Sum applies the "sum" aggregation function on the given field of each group.
+func Sum(field string) Aggregate {
+	return Aggregate{
+		SQL: func(s *sql.Selector) string {
+			return sql.Sum(s.C(field))
+		},
+	}
+}
+
+// ErrNotFound returns when trying to fetch a specific entity and it was not found in the database.
+type ErrNotFound struct {
+	label string
+}
+
+// Error implements the error interface.
+func (e *ErrNotFound) Error() string {
+	return fmt.Sprintf("ent: %s not found", e.label)
+}
+
+// IsNotFound returns a boolean indicating whether the error is a not found error.
+func IsNotFound(err error) bool {
+	_, ok := err.(*ErrNotFound)
+	return ok
+}
+
+// MaskNotFound masks nor found error.
+func MaskNotFound(err error) error {
+	if IsNotFound(err) {
+		return nil
+	}
+	return err
+}
+
+// ErrNotSingular returns when trying to fetch a singular entity and more then one was found in the database.
+type ErrNotSingular struct {
+	label string
+}
+
+// Error implements the error interface.
+func (e *ErrNotSingular) Error() string {
+	return fmt.Sprintf("ent: %s not singular", e.label)
+}
+
+// IsNotSingular returns a boolean indicating whether the error is a not singular error.
+func IsNotSingular(err error) bool {
+	_, ok := err.(*ErrNotSingular)
+	return ok
+}
+
+// ErrConstraintFailed returns when trying to create/update one or more entities and
+// one or more of their constraints failed. For example, violation of edge or field uniqueness.
+type ErrConstraintFailed struct {
+	msg  string
+	wrap error
+}
+
+// Error implements the error interface.
+func (e ErrConstraintFailed) Error() string {
+	return fmt.Sprintf("ent: unique constraint failed: %s", e.msg)
+}
+
+// Unwrap implements the errors.Wrapper interface.
+func (e *ErrConstraintFailed) Unwrap() error {
+	return e.wrap
+}
+
+// IsConstraintFailure returns a boolean indicating whether the error is a constraint failure.
+func IsConstraintFailure(err error) bool {
+	_, ok := err.(*ErrConstraintFailed)
+	return ok
+}
+
+func isSQLConstraintError(err error) (*ErrConstraintFailed, bool) {
+	// Error number 1062 is ER_DUP_ENTRY in mysql, and "UNIQUE constraint failed" is SQLite prefix.
+	if msg := err.Error(); strings.HasPrefix(msg, "Error 1062") || strings.HasPrefix(msg, "UNIQUE constraint failed") {
+		return &ErrConstraintFailed{msg, err}, true
+	}
+	return nil, false
+}
+
+// rollback calls to tx.Rollback and wraps the given error with the rollback error if occurred.
+func rollback(tx dialect.Tx, err error) error {
+	if rerr := tx.Rollback(); rerr != nil {
+		err = fmt.Errorf("%s: %v", err.Error(), rerr)
+	}
+	if err, ok := isSQLConstraintError(err); ok {
+		return err
+	}
+	return err
+}
+
+// keys returns the keys/ids from the edge map.
+func keys(m map[int]struct{}) []int {
+	s := make([]int, 0, len(m))
+	for id, _ := range m {
+		s = append(s, id)
+	}
+	return s
+}

examples/start/ent/example_test.go

@@ -0,0 +1,120 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"log"
+	"time"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// dsn for the database. In order to run the tests locally, run the following command:
+//
+//	 ENT_INTEGRATION_ENDPOINT="root:pass@tcp(localhost:3306)/test?parseTime=True" go test -v
+//
+var dsn string
+
+func ExampleCar() {
+	if dsn == "" {
+		return
+	}
+	ctx := context.Background()
+	drv, err := sql.Open("mysql", dsn)
+	if err != nil {
+		log.Fatalf("failed creating database client: %v", err)
+	}
+	defer drv.Close()
+	client := NewClient(Driver(drv))
+	// creating vertices for the car's edges.
+
+	// create car vertex with its edges.
+	c := client.Car.
+		Create().
+		SetModel("string").
+		SetRegisteredAt(time.Now()).
+		SaveX(ctx)
+	log.Println("car created:", c)
+
+	// query edges.
+
+	// Output:
+}
+func ExampleGroup() {
+	if dsn == "" {
+		return
+	}
+	ctx := context.Background()
+	drv, err := sql.Open("mysql", dsn)
+	if err != nil {
+		log.Fatalf("failed creating database client: %v", err)
+	}
+	defer drv.Close()
+	client := NewClient(Driver(drv))
+	// creating vertices for the group's edges.
+	u0 := client.User.
+		Create().
+		SetAge(1).
+		SetName("string").
+		SaveX(ctx)
+	log.Println("user created:", u0)
+
+	// create group vertex with its edges.
+	gr := client.Group.
+		Create().
+		SetName("string").
+		AddUsers(u0).
+		SaveX(ctx)
+	log.Println("group created:", gr)
+
+	// query edges.
+	u0, err = gr.QueryUsers().First(ctx)
+	if err != nil {
+		log.Fatalf("failed querying users: %v", err)
+	}
+	log.Println("users found:", u0)
+
+	// Output:
+}
+func ExampleUser() {
+	if dsn == "" {
+		return
+	}
+	ctx := context.Background()
+	drv, err := sql.Open("mysql", dsn)
+	if err != nil {
+		log.Fatalf("failed creating database client: %v", err)
+	}
+	defer drv.Close()
+	client := NewClient(Driver(drv))
+	// creating vertices for the user's edges.
+	c0 := client.Car.
+		Create().
+		SetModel("string").
+		SetRegisteredAt(time.Now()).
+		SaveX(ctx)
+	log.Println("car created:", c0)
+
+	// create user vertex with its edges.
+	u := client.User.
+		Create().
+		SetAge(1).
+		SetName("string").
+		AddCars(c0).
+		SaveX(ctx)
+	log.Println("user created:", u)
+
+	// query edges.
+	c0, err = u.QueryCars().First(ctx)
+	if err != nil {
+		log.Fatalf("failed querying cars: %v", err)
+	}
+	log.Println("cars found:", c0)
+
+	// Output:
+}

examples/start/ent/generate.go

@@ -0,0 +1,7 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+package ent
+
+//go:generate go run ../../../entc/cmd/entc/entc.go generate --header "Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.\n// This source code is licensed under the Apache 2.0 license found\n// in the LICENSE file in the root directory of this source tree.\n\n// Code generated (@generated) by entc, DO NOT EDIT." ./schema

examples/start/ent/group.go

@@ -0,0 +1,95 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// Group is the model entity for the Group schema.
+type Group struct {
+	config `json:"-"`
+	// ID of the ent.
+	ID int `json:"id,omitempty"`
+	// Name holds the value of the "name" field.
+	Name string `json:"name,omitempty"`
+}
+
+// FromRows scans the sql response data into Group.
+func (gr *Group) FromRows(rows *sql.Rows) error {
+	var vgr struct {
+		ID   int
+		Name sql.NullString
+	}
+	// the order here should be the same as in the `group.Columns`.
+	if err := rows.Scan(
+		&vgr.ID,
+		&vgr.Name,
+	); err != nil {
+		return err
+	}
+	gr.ID = vgr.ID
+	gr.Name = vgr.Name.String
+	return nil
+}
+
+// QueryUsers queries the users edge of the Group.
+func (gr *Group) QueryUsers() *UserQuery {
+	return (&GroupClient{gr.config}).QueryUsers(gr)
+}
+
+// Update returns a builder for updating this Group.
+// Note that, you need to call Group.Unwrap() before calling this method, if this Group
+// was returned from a transaction, and the transaction was committed or rolled back.
+func (gr *Group) Update() *GroupUpdateOne {
+	return (&GroupClient{gr.config}).UpdateOne(gr)
+}
+
+// Unwrap unwraps the entity that was returned from a transaction after it was closed,
+// so that all next queries will be executed through the driver which created the transaction.
+func (gr *Group) Unwrap() *Group {
+	tx, ok := gr.config.driver.(*txDriver)
+	if !ok {
+		panic("ent: Group is not a transactional entity")
+	}
+	gr.config.driver = tx.drv
+	return gr
+}
+
+// String implements the fmt.Stringer.
+func (gr *Group) String() string {
+	buf := bytes.NewBuffer(nil)
+	buf.WriteString("Group(")
+	buf.WriteString(fmt.Sprintf("id=%v", gr.ID))
+	buf.WriteString(fmt.Sprintf(", name=%v", gr.Name))
+	buf.WriteString(")")
+	return buf.String()
+}
+
+// Groups is a parsable slice of Group.
+type Groups []*Group
+
+// FromRows scans the sql response data into Groups.
+func (gr *Groups) FromRows(rows *sql.Rows) error {
+	for rows.Next() {
+		vgr := &Group{}
+		if err := vgr.FromRows(rows); err != nil {
+			return err
+		}
+		*gr = append(*gr, vgr)
+	}
+	return nil
+}
+
+func (gr Groups) config(cfg config) {
+	for i := range gr {
+		gr[i].config = cfg
+	}
+}

examples/start/ent/group/group.go

@@ -0,0 +1,49 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package group
+
+import (
+	"github.com/facebookincubator/ent/examples/start/ent/schema"
+)
+
+const (
+	// Label holds the string label denoting the group type in the database.
+	Label = "group"
+	// FieldID holds the string denoting the id field in the database.
+	FieldID = "id"
+	// FieldName holds the string denoting the name vertex property in the database.
+	FieldName = "name"
+
+	// Table holds the table name of the group in the database.
+	Table = "groups"
+	// UsersTable is the table the holds the users relation/edge. The primary key declared below.
+	UsersTable = "group_users"
+	// UsersInverseTable is the table name for the User entity.
+	// It exists in this package in order to avoid circular dependency with the "user" package.
+	UsersInverseTable = "users"
+)
+
+// Columns holds all SQL columns are group fields.
+var Columns = []string{
+	FieldID,
+	FieldName,
+}
+
+var (
+	// UsersPrimaryKey and UsersColumn2 are the table columns denoting the
+	// primary key for the users relation (M2M).
+	UsersPrimaryKey = []string{"group_id", "user_id"}
+)
+
+var (
+	fields = schema.Group{}.Fields()
+
+	// descName is the schema descriptor for name field.
+	descName = fields[0].Descriptor()
+	// NameValidator is a validator for the "name" field. It is called by the builders before save.
+	NameValidator = descName.Validators[0].(func(string) error)
+)

examples/start/ent/group/where.go

@@ -0,0 +1,329 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package group
+
+import (
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+)
+
+// ID filters vertices based on their identifier.
+func ID(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDEQ applies the EQ predicate on the ID field.
+func IDEQ(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDNEQ applies the NEQ predicate on the ID field.
+func IDNEQ(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDIn applies the In predicate on the ID field.
+func IDIn(ids ...int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(ids) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			v := make([]interface{}, len(ids))
+			for i := range v {
+				v[i] = ids[i]
+			}
+			s.Where(sql.In(s.C(FieldID), v...))
+		},
+	)
+}
+
+// IDNotIn applies the NotIn predicate on the ID field.
+func IDNotIn(ids ...int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(ids) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			v := make([]interface{}, len(ids))
+			for i := range v {
+				v[i] = ids[i]
+			}
+			s.Where(sql.NotIn(s.C(FieldID), v...))
+		},
+	)
+}
+
+// IDGT applies the GT predicate on the ID field.
+func IDGT(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDGTE applies the GTE predicate on the ID field.
+func IDGTE(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDLT applies the LT predicate on the ID field.
+func IDLT(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDLTE applies the LTE predicate on the ID field.
+func IDLTE(id int) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldID), id))
+		},
+	)
+}
+
+// Name applies equality check predicate on the "name" field. It's identical to NameEQ.
+func Name(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameEQ applies the EQ predicate on the "name" field.
+func NameEQ(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameNEQ applies the NEQ predicate on the "name" field.
+func NameNEQ(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameIn applies the In predicate on the "name" field.
+func NameIn(vs ...string) predicate.Group {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.Group(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.In(s.C(FieldName), v...))
+		},
+	)
+}
+
+// NameNotIn applies the NotIn predicate on the "name" field.
+func NameNotIn(vs ...string) predicate.Group {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.Group(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.NotIn(s.C(FieldName), v...))
+		},
+	)
+}
+
+// NameGT applies the GT predicate on the "name" field.
+func NameGT(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameGTE applies the GTE predicate on the "name" field.
+func NameGTE(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameLT applies the LT predicate on the "name" field.
+func NameLT(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameLTE applies the LTE predicate on the "name" field.
+func NameLTE(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameContains applies the Contains predicate on the "name" field.
+func NameContains(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.Contains(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameHasPrefix applies the HasPrefix predicate on the "name" field.
+func NameHasPrefix(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.HasPrefix(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameHasSuffix applies the HasSuffix predicate on the "name" field.
+func NameHasSuffix(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.HasSuffix(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameEqualFold applies the EqualFold predicate on the "name" field.
+func NameEqualFold(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.EqualFold(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameContainsFold applies the ContainsFold predicate on the "name" field.
+func NameContainsFold(v string) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			s.Where(sql.ContainsFold(s.C(FieldName), v))
+		},
+	)
+}
+
+// HasUsers applies the HasEdge predicate on the "users" edge.
+func HasUsers() predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			s.Where(
+				sql.In(
+					t1.C(FieldID),
+					sql.Select(UsersPrimaryKey[0]).From(sql.Table(UsersTable)),
+				),
+			)
+		},
+	)
+}
+
+// HasUsersWith applies the HasEdge predicate on the "users" edge with a given conditions (other predicates).
+func HasUsersWith(preds ...predicate.User) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			t2 := sql.Table(UsersInverseTable)
+			t3 := sql.Table(UsersTable)
+			t4 := sql.Select(t3.C(UsersPrimaryKey[0])).
+				From(t3).
+				Join(t2).
+				On(t3.C(UsersPrimaryKey[1]), t2.C(FieldID))
+			t5 := sql.Select().From(t2)
+			for _, p := range preds {
+				p(t5)
+			}
+			t4.FromSelect(t5)
+			s.Where(sql.In(t1.C(FieldID), t4))
+		},
+	)
+}
+
+// And groups list of predicates with the AND operator between them.
+func And(predicates ...predicate.Group) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			for _, p := range predicates {
+				p(s)
+			}
+		},
+	)
+}
+
+// Or groups list of predicates with the OR operator between them.
+func Or(predicates ...predicate.Group) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			for i, p := range predicates {
+				if i > 0 {
+					s.Or()
+				}
+				p(s)
+			}
+		},
+	)
+}
+
+// Not applies the not operator on the given predicate.
+func Not(p predicate.Group) predicate.Group {
+	return predicate.Group(
+		func(s *sql.Selector) {
+			p(s.Not())
+		},
+	)
+}

examples/start/ent/group_create.go

@@ -0,0 +1,110 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+)
+
+// GroupCreate is the builder for creating a Group entity.
+type GroupCreate struct {
+	config
+	name  *string
+	users map[int]struct{}
+}
+
+// SetName sets the name field.
+func (gc *GroupCreate) SetName(s string) *GroupCreate {
+	gc.name = &s
+	return gc
+}
+
+// AddUserIDs adds the users edge to User by ids.
+func (gc *GroupCreate) AddUserIDs(ids ...int) *GroupCreate {
+	if gc.users == nil {
+		gc.users = make(map[int]struct{})
+	}
+	for i := range ids {
+		gc.users[ids[i]] = struct{}{}
+	}
+	return gc
+}
+
+// AddUsers adds the users edges to User.
+func (gc *GroupCreate) AddUsers(u ...*User) *GroupCreate {
+	ids := make([]int, len(u))
+	for i := range u {
+		ids[i] = u[i].ID
+	}
+	return gc.AddUserIDs(ids...)
+}
+
+// Save creates the Group in the database.
+func (gc *GroupCreate) Save(ctx context.Context) (*Group, error) {
+	if gc.name == nil {
+		return nil, errors.New("ent: missing required field \"name\"")
+	}
+	if err := group.NameValidator(*gc.name); err != nil {
+		return nil, fmt.Errorf("ent: validator failed for field \"name\": %v", err)
+	}
+	return gc.sqlSave(ctx)
+}
+
+// SaveX calls Save and panics if Save returns an error.
+func (gc *GroupCreate) SaveX(ctx context.Context) *Group {
+	v, err := gc.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (gc *GroupCreate) sqlSave(ctx context.Context) (*Group, error) {
+	var (
+		res sql.Result
+		gr  = &Group{config: gc.config}
+	)
+	tx, err := gc.driver.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	builder := sql.Insert(group.Table).Default(gc.driver.Dialect())
+	if value := gc.name; value != nil {
+		builder.Set(group.FieldName, *value)
+		gr.Name = *value
+	}
+	query, args := builder.Query()
+	if err := tx.Exec(ctx, query, args, &res); err != nil {
+		return nil, rollback(tx, err)
+	}
+	id, err := res.LastInsertId()
+	if err != nil {
+		return nil, rollback(tx, err)
+	}
+	gr.ID = int(id)
+	if len(gc.users) > 0 {
+		for eid := range gc.users {
+
+			query, args := sql.Insert(group.UsersTable).
+				Columns(group.UsersPrimaryKey[0], group.UsersPrimaryKey[1]).
+				Values(id, eid).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return nil, rollback(tx, err)
+			}
+		}
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return gr, nil
+}

examples/start/ent/group_delete.go

@@ -0,0 +1,81 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+)
+
+// GroupDelete is the builder for deleting a Group entity.
+type GroupDelete struct {
+	config
+	predicates []predicate.Group
+}
+
+// Where adds a new predicate to the delete builder.
+func (gd *GroupDelete) Where(ps ...predicate.Group) *GroupDelete {
+	gd.predicates = append(gd.predicates, ps...)
+	return gd
+}
+
+// Exec executes the deletion query and returns how many vertices were deleted.
+func (gd *GroupDelete) Exec(ctx context.Context) (int, error) {
+	return gd.sqlExec(ctx)
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (gd *GroupDelete) ExecX(ctx context.Context) int {
+	n, err := gd.Exec(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+func (gd *GroupDelete) sqlExec(ctx context.Context) (int, error) {
+	var res sql.Result
+	selector := sql.Select().From(sql.Table(group.Table))
+	for _, p := range gd.predicates {
+		p(selector)
+	}
+	query, args := sql.Delete(group.Table).FromSelect(selector).Query()
+	if err := gd.driver.Exec(ctx, query, args, &res); err != nil {
+		return 0, err
+	}
+	affected, err := res.RowsAffected()
+	if err != nil {
+		return 0, err
+	}
+	return int(affected), nil
+}
+
+// GroupDeleteOne is the builder for deleting a single Group entity.
+type GroupDeleteOne struct {
+	gd *GroupDelete
+}
+
+// Exec executes the deletion query.
+func (gdo *GroupDeleteOne) Exec(ctx context.Context) error {
+	n, err := gdo.gd.Exec(ctx)
+	switch {
+	case err != nil:
+		return err
+	case n == 0:
+		return &ErrNotFound{group.Label}
+	default:
+		return nil
+	}
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (gdo *GroupDeleteOne) ExecX(ctx context.Context) {
+	gdo.gd.ExecX(ctx)
+}

examples/start/ent/group_query.go

@@ -0,0 +1,615 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// GroupQuery is the builder for querying Group entities.
+type GroupQuery struct {
+	config
+	limit      *int
+	offset     *int
+	order      []Order
+	unique     []string
+	predicates []predicate.Group
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Where adds a new predicate for the builder.
+func (gq *GroupQuery) Where(ps ...predicate.Group) *GroupQuery {
+	gq.predicates = append(gq.predicates, ps...)
+	return gq
+}
+
+// Limit adds a limit step to the query.
+func (gq *GroupQuery) Limit(limit int) *GroupQuery {
+	gq.limit = &limit
+	return gq
+}
+
+// Offset adds an offset step to the query.
+func (gq *GroupQuery) Offset(offset int) *GroupQuery {
+	gq.offset = &offset
+	return gq
+}
+
+// Order adds an order step to the query.
+func (gq *GroupQuery) Order(o ...Order) *GroupQuery {
+	gq.order = append(gq.order, o...)
+	return gq
+}
+
+// QueryUsers chains the current query on the users edge.
+func (gq *GroupQuery) QueryUsers() *UserQuery {
+	query := &UserQuery{config: gq.config}
+	t1 := sql.Table(user.Table)
+	t2 := gq.sqlQuery()
+	t2.Select(t2.C(group.FieldID))
+	t3 := sql.Table(group.UsersTable)
+	t4 := sql.Select(t3.C(group.UsersPrimaryKey[1])).
+		From(t3).
+		Join(t2).
+		On(t3.C(group.UsersPrimaryKey[0]), t2.C(group.FieldID))
+	query.sql = sql.Select().
+		From(t1).
+		Join(t4).
+		On(t1.C(user.FieldID), t4.C(group.UsersPrimaryKey[1]))
+	return query
+}
+
+// First returns the first Group entity in the query. Returns *ErrNotFound when no group was found.
+func (gq *GroupQuery) First(ctx context.Context) (*Group, error) {
+	grs, err := gq.Limit(1).All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if len(grs) == 0 {
+		return nil, &ErrNotFound{group.Label}
+	}
+	return grs[0], nil
+}
+
+// FirstX is like First, but panics if an error occurs.
+func (gq *GroupQuery) FirstX(ctx context.Context) *Group {
+	gr, err := gq.First(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return gr
+}
+
+// FirstID returns the first Group id in the query. Returns *ErrNotFound when no id was found.
+func (gq *GroupQuery) FirstID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = gq.Limit(1).IDs(ctx); err != nil {
+		return
+	}
+	if len(ids) == 0 {
+		err = &ErrNotFound{group.Label}
+		return
+	}
+	return ids[0], nil
+}
+
+// FirstXID is like FirstID, but panics if an error occurs.
+func (gq *GroupQuery) FirstXID(ctx context.Context) int {
+	id, err := gq.FirstID(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return id
+}
+
+// Only returns the only Group entity in the query, returns an error if not exactly one entity was returned.
+func (gq *GroupQuery) Only(ctx context.Context) (*Group, error) {
+	grs, err := gq.Limit(2).All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	switch len(grs) {
+	case 1:
+		return grs[0], nil
+	case 0:
+		return nil, &ErrNotFound{group.Label}
+	default:
+		return nil, &ErrNotSingular{group.Label}
+	}
+}
+
+// OnlyX is like Only, but panics if an error occurs.
+func (gq *GroupQuery) OnlyX(ctx context.Context) *Group {
+	gr, err := gq.Only(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return gr
+}
+
+// OnlyID returns the only Group id in the query, returns an error if not exactly one id was returned.
+func (gq *GroupQuery) OnlyID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = gq.Limit(2).IDs(ctx); err != nil {
+		return
+	}
+	switch len(ids) {
+	case 1:
+		id = ids[0]
+	case 0:
+		err = &ErrNotFound{group.Label}
+	default:
+		err = &ErrNotSingular{group.Label}
+	}
+	return
+}
+
+// OnlyXID is like OnlyID, but panics if an error occurs.
+func (gq *GroupQuery) OnlyXID(ctx context.Context) int {
+	id, err := gq.OnlyID(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+// All executes the query and returns a list of Groups.
+func (gq *GroupQuery) All(ctx context.Context) ([]*Group, error) {
+	return gq.sqlAll(ctx)
+}
+
+// AllX is like All, but panics if an error occurs.
+func (gq *GroupQuery) AllX(ctx context.Context) []*Group {
+	grs, err := gq.All(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return grs
+}
+
+// IDs executes the query and returns a list of Group ids.
+func (gq *GroupQuery) IDs(ctx context.Context) ([]int, error) {
+	return gq.sqlIDs(ctx)
+}
+
+// IDsX is like IDs, but panics if an error occurs.
+func (gq *GroupQuery) IDsX(ctx context.Context) []int {
+	ids, err := gq.IDs(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return ids
+}
+
+// Count returns the count of the given query.
+func (gq *GroupQuery) Count(ctx context.Context) (int, error) {
+	return gq.sqlCount(ctx)
+}
+
+// CountX is like Count, but panics if an error occurs.
+func (gq *GroupQuery) CountX(ctx context.Context) int {
+	count, err := gq.Count(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return count
+}
+
+// Exist returns true if the query has elements in the graph.
+func (gq *GroupQuery) Exist(ctx context.Context) (bool, error) {
+	return gq.sqlExist(ctx)
+}
+
+// ExistX is like Exist, but panics if an error occurs.
+func (gq *GroupQuery) ExistX(ctx context.Context) bool {
+	exist, err := gq.Exist(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return exist
+}
+
+// Clone returns a duplicate of the query builder, including all associated steps. It can be
+// used to prepare common query builders and use them differently after the clone is made.
+func (gq *GroupQuery) Clone() *GroupQuery {
+	return &GroupQuery{
+		config:     gq.config,
+		limit:      gq.limit,
+		offset:     gq.offset,
+		order:      append([]Order{}, gq.order...),
+		unique:     append([]string{}, gq.unique...),
+		predicates: append([]predicate.Group{}, gq.predicates...),
+		// clone intermediate queries.
+		sql: gq.sql.Clone(),
+	}
+}
+
+// GroupBy used to group vertices by one or more fields/columns.
+// It is often used with aggregate functions, like: count, max, mean, min, sum.
+//
+// Example:
+//
+//	var v []struct {
+//		Name string `json:"name,omitempty"`
+//		Count int `json:"count,omitempty"`
+//	}
+//
+//	client.Group.Query().
+//		GroupBy(group.FieldName).
+//		Aggregate(ent.Count()).
+//		Scan(ctx, &v)
+//
+func (gq *GroupQuery) GroupBy(field string, fields ...string) *GroupGroupBy {
+	group := &GroupGroupBy{config: gq.config}
+	group.fields = append([]string{field}, fields...)
+	group.sql = gq.sqlQuery()
+	return group
+}
+
+// Select one or more fields from the given query.
+//
+// Example:
+//
+//	var v []struct {
+//		Name string `json:"name,omitempty"`
+//	}
+//
+//	client.Group.Query().
+//		Select(group.FieldName).
+//		Scan(ctx, &v)
+//
+func (gq *GroupQuery) Select(field string, fields ...string) *GroupSelect {
+	selector := &GroupSelect{config: gq.config}
+	selector.fields = append([]string{field}, fields...)
+	selector.sql = gq.sqlQuery()
+	return selector
+}
+
+func (gq *GroupQuery) sqlAll(ctx context.Context) ([]*Group, error) {
+	rows := &sql.Rows{}
+	selector := gq.sqlQuery()
+	if unique := gq.unique; len(unique) == 0 {
+		selector.Distinct()
+	}
+	query, args := selector.Query()
+	if err := gq.driver.Query(ctx, query, args, rows); err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var grs Groups
+	if err := grs.FromRows(rows); err != nil {
+		return nil, err
+	}
+	grs.config(gq.config)
+	return grs, nil
+}
+
+func (gq *GroupQuery) sqlCount(ctx context.Context) (int, error) {
+	rows := &sql.Rows{}
+	selector := gq.sqlQuery()
+	unique := []string{group.FieldID}
+	if len(gq.unique) > 0 {
+		unique = gq.unique
+	}
+	selector.Count(sql.Distinct(selector.Columns(unique...)...))
+	query, args := selector.Query()
+	if err := gq.driver.Query(ctx, query, args, rows); err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+	if !rows.Next() {
+		return 0, errors.New("ent: no rows found")
+	}
+	var n int
+	if err := rows.Scan(&n); err != nil {
+		return 0, fmt.Errorf("ent: failed reading count: %v", err)
+	}
+	return n, nil
+}
+
+func (gq *GroupQuery) sqlExist(ctx context.Context) (bool, error) {
+	n, err := gq.sqlCount(ctx)
+	if err != nil {
+		return false, fmt.Errorf("ent: check existence: %v", err)
+	}
+	return n > 0, nil
+}
+
+func (gq *GroupQuery) sqlIDs(ctx context.Context) ([]int, error) {
+	vs, err := gq.sqlAll(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var ids []int
+	for _, v := range vs {
+		ids = append(ids, v.ID)
+	}
+	return ids, nil
+}
+
+func (gq *GroupQuery) sqlQuery() *sql.Selector {
+	t1 := sql.Table(group.Table)
+	selector := sql.Select(t1.Columns(group.Columns...)...).From(t1)
+	if gq.sql != nil {
+		selector = gq.sql
+		selector.Select(selector.Columns(group.Columns...)...)
+	}
+	for _, p := range gq.predicates {
+		p(selector)
+	}
+	for _, p := range gq.order {
+		p(selector)
+	}
+	if offset := gq.offset; offset != nil {
+		// limit is mandatory for offset clause. We start
+		// with default value, and override it below if needed.
+		selector.Offset(*offset).Limit(math.MaxInt64)
+	}
+	if limit := gq.limit; limit != nil {
+		selector.Limit(*limit)
+	}
+	return selector
+}
+
+// GroupGroupBy is the builder for group-by Group entities.
+type GroupGroupBy struct {
+	config
+	fields []string
+	fns    []Aggregate
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Aggregate adds the given aggregation functions to the group-by query.
+func (ggb *GroupGroupBy) Aggregate(fns ...Aggregate) *GroupGroupBy {
+	ggb.fns = append(ggb.fns, fns...)
+	return ggb
+}
+
+// Scan applies the group-by query and scan the result into the given value.
+func (ggb *GroupGroupBy) Scan(ctx context.Context, v interface{}) error {
+	return ggb.sqlScan(ctx, v)
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (ggb *GroupGroupBy) ScanX(ctx context.Context, v interface{}) {
+	if err := ggb.Scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from group-by. It is only allowed when querying group-by with one field.
+func (ggb *GroupGroupBy) Strings(ctx context.Context) ([]string, error) {
+	if len(ggb.fields) > 1 {
+		return nil, errors.New("ent: GroupGroupBy.Strings is not achievable when grouping more than 1 field")
+	}
+	var v []string
+	if err := ggb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (ggb *GroupGroupBy) StringsX(ctx context.Context) []string {
+	v, err := ggb.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from group-by. It is only allowed when querying group-by with one field.
+func (ggb *GroupGroupBy) Ints(ctx context.Context) ([]int, error) {
+	if len(ggb.fields) > 1 {
+		return nil, errors.New("ent: GroupGroupBy.Ints is not achievable when grouping more than 1 field")
+	}
+	var v []int
+	if err := ggb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (ggb *GroupGroupBy) IntsX(ctx context.Context) []int {
+	v, err := ggb.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from group-by. It is only allowed when querying group-by with one field.
+func (ggb *GroupGroupBy) Float64s(ctx context.Context) ([]float64, error) {
+	if len(ggb.fields) > 1 {
+		return nil, errors.New("ent: GroupGroupBy.Float64s is not achievable when grouping more than 1 field")
+	}
+	var v []float64
+	if err := ggb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (ggb *GroupGroupBy) Float64sX(ctx context.Context) []float64 {
+	v, err := ggb.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from group-by. It is only allowed when querying group-by with one field.
+func (ggb *GroupGroupBy) Bools(ctx context.Context) ([]bool, error) {
+	if len(ggb.fields) > 1 {
+		return nil, errors.New("ent: GroupGroupBy.Bools is not achievable when grouping more than 1 field")
+	}
+	var v []bool
+	if err := ggb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (ggb *GroupGroupBy) BoolsX(ctx context.Context) []bool {
+	v, err := ggb.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (ggb *GroupGroupBy) sqlScan(ctx context.Context, v interface{}) error {
+	rows := &sql.Rows{}
+	query, args := ggb.sqlQuery().Query()
+	if err := ggb.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+func (ggb *GroupGroupBy) sqlQuery() *sql.Selector {
+	selector := ggb.sql
+	columns := make([]string, 0, len(ggb.fields)+len(ggb.fns))
+	columns = append(columns, ggb.fields...)
+	for _, fn := range ggb.fns {
+		columns = append(columns, fn.SQL(selector))
+	}
+	return selector.Select(columns...).GroupBy(ggb.fields...)
+}
+
+// GroupSelect is the builder for select fields of Group entities.
+type GroupSelect struct {
+	config
+	fields []string
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Scan applies the selector query and scan the result into the given value.
+func (gs *GroupSelect) Scan(ctx context.Context, v interface{}) error {
+	return gs.sqlScan(ctx, v)
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (gs *GroupSelect) ScanX(ctx context.Context, v interface{}) {
+	if err := gs.Scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from selector. It is only allowed when selecting one field.
+func (gs *GroupSelect) Strings(ctx context.Context) ([]string, error) {
+	if len(gs.fields) > 1 {
+		return nil, errors.New("ent: GroupSelect.Strings is not achievable when selecting more than 1 field")
+	}
+	var v []string
+	if err := gs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (gs *GroupSelect) StringsX(ctx context.Context) []string {
+	v, err := gs.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from selector. It is only allowed when selecting one field.
+func (gs *GroupSelect) Ints(ctx context.Context) ([]int, error) {
+	if len(gs.fields) > 1 {
+		return nil, errors.New("ent: GroupSelect.Ints is not achievable when selecting more than 1 field")
+	}
+	var v []int
+	if err := gs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (gs *GroupSelect) IntsX(ctx context.Context) []int {
+	v, err := gs.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from selector. It is only allowed when selecting one field.
+func (gs *GroupSelect) Float64s(ctx context.Context) ([]float64, error) {
+	if len(gs.fields) > 1 {
+		return nil, errors.New("ent: GroupSelect.Float64s is not achievable when selecting more than 1 field")
+	}
+	var v []float64
+	if err := gs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (gs *GroupSelect) Float64sX(ctx context.Context) []float64 {
+	v, err := gs.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from selector. It is only allowed when selecting one field.
+func (gs *GroupSelect) Bools(ctx context.Context) ([]bool, error) {
+	if len(gs.fields) > 1 {
+		return nil, errors.New("ent: GroupSelect.Bools is not achievable when selecting more than 1 field")
+	}
+	var v []bool
+	if err := gs.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (gs *GroupSelect) BoolsX(ctx context.Context) []bool {
+	v, err := gs.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (gs *GroupSelect) sqlScan(ctx context.Context, v interface{}) error {
+	rows := &sql.Rows{}
+	query, args := gs.sqlQuery().Query()
+	if err := gs.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+func (gs *GroupSelect) sqlQuery() sql.Querier {
+	view := "group_view"
+	return sql.Select(gs.fields...).From(gs.sql.As(view))
+}

examples/start/ent/group_update.go

@@ -0,0 +1,352 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+)
+
+// GroupUpdate is the builder for updating Group entities.
+type GroupUpdate struct {
+	config
+	name         *string
+	users        map[int]struct{}
+	removedUsers map[int]struct{}
+	predicates   []predicate.Group
+}
+
+// Where adds a new predicate for the builder.
+func (gu *GroupUpdate) Where(ps ...predicate.Group) *GroupUpdate {
+	gu.predicates = append(gu.predicates, ps...)
+	return gu
+}
+
+// SetName sets the name field.
+func (gu *GroupUpdate) SetName(s string) *GroupUpdate {
+	gu.name = &s
+	return gu
+}
+
+// AddUserIDs adds the users edge to User by ids.
+func (gu *GroupUpdate) AddUserIDs(ids ...int) *GroupUpdate {
+	if gu.users == nil {
+		gu.users = make(map[int]struct{})
+	}
+	for i := range ids {
+		gu.users[ids[i]] = struct{}{}
+	}
+	return gu
+}
+
+// AddUsers adds the users edges to User.
+func (gu *GroupUpdate) AddUsers(u ...*User) *GroupUpdate {
+	ids := make([]int, len(u))
+	for i := range u {
+		ids[i] = u[i].ID
+	}
+	return gu.AddUserIDs(ids...)
+}
+
+// RemoveUserIDs removes the users edge to User by ids.
+func (gu *GroupUpdate) RemoveUserIDs(ids ...int) *GroupUpdate {
+	if gu.removedUsers == nil {
+		gu.removedUsers = make(map[int]struct{})
+	}
+	for i := range ids {
+		gu.removedUsers[ids[i]] = struct{}{}
+	}
+	return gu
+}
+
+// RemoveUsers removes users edges to User.
+func (gu *GroupUpdate) RemoveUsers(u ...*User) *GroupUpdate {
+	ids := make([]int, len(u))
+	for i := range u {
+		ids[i] = u[i].ID
+	}
+	return gu.RemoveUserIDs(ids...)
+}
+
+// Save executes the query and returns the number of rows/vertices matched by this operation.
+func (gu *GroupUpdate) Save(ctx context.Context) (int, error) {
+	if gu.name != nil {
+		if err := group.NameValidator(*gu.name); err != nil {
+			return 0, fmt.Errorf("ent: validator failed for field \"name\": %v", err)
+		}
+	}
+	return gu.sqlSave(ctx)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (gu *GroupUpdate) SaveX(ctx context.Context) int {
+	affected, err := gu.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return affected
+}
+
+// Exec executes the query.
+func (gu *GroupUpdate) Exec(ctx context.Context) error {
+	_, err := gu.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (gu *GroupUpdate) ExecX(ctx context.Context) {
+	if err := gu.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (gu *GroupUpdate) sqlSave(ctx context.Context) (n int, err error) {
+	selector := sql.Select(group.FieldID).From(sql.Table(group.Table))
+	for _, p := range gu.predicates {
+		p(selector)
+	}
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err = gu.driver.Query(ctx, query, args, rows); err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+	var ids []int
+	for rows.Next() {
+		var id int
+		if err := rows.Scan(&id); err != nil {
+			return 0, fmt.Errorf("ent: failed reading id: %v", err)
+		}
+		ids = append(ids, id)
+	}
+	if len(ids) == 0 {
+		return 0, nil
+	}
+
+	tx, err := gu.driver.Tx(ctx)
+	if err != nil {
+		return 0, err
+	}
+	var (
+		res     sql.Result
+		builder = sql.Update(group.Table).Where(sql.InInts(group.FieldID, ids...))
+	)
+	if value := gu.name; value != nil {
+		builder.Set(group.FieldName, *value)
+	}
+	if !builder.Empty() {
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if len(gu.removedUsers) > 0 {
+		eids := make([]int, len(gu.removedUsers))
+		for eid := range gu.removedUsers {
+			eids = append(eids, eid)
+		}
+		query, args := sql.Delete(group.UsersTable).
+			Where(sql.InInts(group.UsersPrimaryKey[0], ids...)).
+			Where(sql.InInts(group.UsersPrimaryKey[1], eids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if len(gu.users) > 0 {
+		values := make([][]int, 0, len(ids))
+		for _, id := range ids {
+			for eid := range gu.users {
+				values = append(values, []int{id, eid})
+			}
+		}
+		builder := sql.Insert(group.UsersTable).
+			Columns(group.UsersPrimaryKey[0], group.UsersPrimaryKey[1])
+		for _, v := range values {
+			builder.Values(v[0], v[1])
+		}
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return 0, err
+	}
+	return len(ids), nil
+}
+
+// GroupUpdateOne is the builder for updating a single Group entity.
+type GroupUpdateOne struct {
+	config
+	id           int
+	name         *string
+	users        map[int]struct{}
+	removedUsers map[int]struct{}
+}
+
+// SetName sets the name field.
+func (guo *GroupUpdateOne) SetName(s string) *GroupUpdateOne {
+	guo.name = &s
+	return guo
+}
+
+// AddUserIDs adds the users edge to User by ids.
+func (guo *GroupUpdateOne) AddUserIDs(ids ...int) *GroupUpdateOne {
+	if guo.users == nil {
+		guo.users = make(map[int]struct{})
+	}
+	for i := range ids {
+		guo.users[ids[i]] = struct{}{}
+	}
+	return guo
+}
+
+// AddUsers adds the users edges to User.
+func (guo *GroupUpdateOne) AddUsers(u ...*User) *GroupUpdateOne {
+	ids := make([]int, len(u))
+	for i := range u {
+		ids[i] = u[i].ID
+	}
+	return guo.AddUserIDs(ids...)
+}
+
+// RemoveUserIDs removes the users edge to User by ids.
+func (guo *GroupUpdateOne) RemoveUserIDs(ids ...int) *GroupUpdateOne {
+	if guo.removedUsers == nil {
+		guo.removedUsers = make(map[int]struct{})
+	}
+	for i := range ids {
+		guo.removedUsers[ids[i]] = struct{}{}
+	}
+	return guo
+}
+
+// RemoveUsers removes users edges to User.
+func (guo *GroupUpdateOne) RemoveUsers(u ...*User) *GroupUpdateOne {
+	ids := make([]int, len(u))
+	for i := range u {
+		ids[i] = u[i].ID
+	}
+	return guo.RemoveUserIDs(ids...)
+}
+
+// Save executes the query and returns the updated entity.
+func (guo *GroupUpdateOne) Save(ctx context.Context) (*Group, error) {
+	if guo.name != nil {
+		if err := group.NameValidator(*guo.name); err != nil {
+			return nil, fmt.Errorf("ent: validator failed for field \"name\": %v", err)
+		}
+	}
+	return guo.sqlSave(ctx)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (guo *GroupUpdateOne) SaveX(ctx context.Context) *Group {
+	gr, err := guo.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return gr
+}
+
+// Exec executes the query on the entity.
+func (guo *GroupUpdateOne) Exec(ctx context.Context) error {
+	_, err := guo.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (guo *GroupUpdateOne) ExecX(ctx context.Context) {
+	if err := guo.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (guo *GroupUpdateOne) sqlSave(ctx context.Context) (gr *Group, err error) {
+	selector := sql.Select(group.Columns...).From(sql.Table(group.Table))
+	group.ID(guo.id)(selector)
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err = guo.driver.Query(ctx, query, args, rows); err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []int
+	for rows.Next() {
+		var id int
+		gr = &Group{config: guo.config}
+		if err := gr.FromRows(rows); err != nil {
+			return nil, fmt.Errorf("ent: failed scanning row into Group: %v", err)
+		}
+		id = gr.ID
+		ids = append(ids, id)
+	}
+	switch n := len(ids); {
+	case n == 0:
+		return nil, fmt.Errorf("ent: Group not found with id: %v", guo.id)
+	case n > 1:
+		return nil, fmt.Errorf("ent: more than one Group with the same id: %v", guo.id)
+	}
+
+	tx, err := guo.driver.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var (
+		res     sql.Result
+		builder = sql.Update(group.Table).Where(sql.InInts(group.FieldID, ids...))
+	)
+	if value := guo.name; value != nil {
+		builder.Set(group.FieldName, *value)
+		gr.Name = *value
+	}
+	if !builder.Empty() {
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if len(guo.removedUsers) > 0 {
+		eids := make([]int, len(guo.removedUsers))
+		for eid := range guo.removedUsers {
+			eids = append(eids, eid)
+		}
+		query, args := sql.Delete(group.UsersTable).
+			Where(sql.InInts(group.UsersPrimaryKey[0], ids...)).
+			Where(sql.InInts(group.UsersPrimaryKey[1], eids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if len(guo.users) > 0 {
+		values := make([][]int, 0, len(ids))
+		for _, id := range ids {
+			for eid := range guo.users {
+				values = append(values, []int{id, eid})
+			}
+		}
+		builder := sql.Insert(group.UsersTable).
+			Columns(group.UsersPrimaryKey[0], group.UsersPrimaryKey[1])
+		for _, v := range values {
+			builder.Values(v[0], v[1])
+		}
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return nil, err
+	}
+	return gr, nil
+}

examples/start/ent/migrate/migrate.go

@@ -0,0 +1,71 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package migrate
+
+import (
+	"context"
+	"fmt"
+	"io"
+
+	"github.com/facebookincubator/ent/dialect"
+	"github.com/facebookincubator/ent/dialect/sql/schema"
+)
+
+var (
+	// WithGlobalUniqueID sets the universal ids options to the migration.
+	// If this option is enabled, ent migration will allocate a 1<<32 range
+	// for the ids of each entity (table).
+	// Note that this option cannot be applied on tables that already exist.
+	WithGlobalUniqueID = schema.WithGlobalUniqueID
+	// WithDropColumn sets the drop column option to the migration.
+	// If this option is enabled, ent migration will drop old columns
+	// that were used for both fields and edges. This defaults to false.
+	WithDropColumn = schema.WithDropColumn
+	// WithDropIndex sets the drop index option to the migration.
+	// If this option is enabled, ent migration will drop old indexes
+	// that were defined in the schema. This defaults to false.
+	// Note that unique constraints are defined using `UNIQUE INDEX`,
+	// and therefore, it's recommended to enable this option to get more
+	// flexibility in the schema changes.
+	WithDropIndex = schema.WithDropIndex
+)
+
+// Schema is the API for creating, migrating and dropping a schema.
+type Schema struct {
+	drv         dialect.Driver
+	universalID bool
+}
+
+// NewSchema creates a new schema client.
+func NewSchema(drv dialect.Driver) *Schema { return &Schema{drv: drv} }
+
+// Create creates all schema resources.
+func (s *Schema) Create(ctx context.Context, opts ...schema.MigrateOption) error {
+	migrate, err := schema.NewMigrate(s.drv, opts...)
+	if err != nil {
+		return fmt.Errorf("ent/migrate: %v", err)
+	}
+	return migrate.Create(ctx, Tables...)
+}
+
+// WriteTo writes the schema changes to w instead of running them against the database.
+//
+// 	if err := client.Schema.WriteTo(context.Background(), os.Stdout); err != nil {
+//		log.Fatal(err)
+// 	}
+//
+func (s *Schema) WriteTo(ctx context.Context, w io.Writer, opts ...schema.MigrateOption) error {
+	drv := &schema.WriteDriver{
+		Writer: w,
+		Driver: s.drv,
+	}
+	migrate, err := schema.NewMigrate(drv, opts...)
+	if err != nil {
+		return fmt.Errorf("ent/migrate: %v", err)
+	}
+	return migrate.Create(ctx, Tables...)
+}

examples/start/ent/migrate/schema.go

@@ -0,0 +1,104 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package migrate
+
+import (
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+
+	"github.com/facebookincubator/ent/dialect/sql/schema"
+	"github.com/facebookincubator/ent/schema/field"
+)
+
+var (
+	// CarsColumns holds the columns for the "cars" table.
+	CarsColumns = []*schema.Column{
+		{Name: "id", Type: field.TypeInt, Increment: true},
+		{Name: "model", Type: field.TypeString},
+		{Name: "registered_at", Type: field.TypeTime},
+		{Name: "owner_id", Type: field.TypeInt, Nullable: true},
+	}
+	// CarsTable holds the schema information for the "cars" table.
+	CarsTable = &schema.Table{
+		Name:       "cars",
+		Columns:    CarsColumns,
+		PrimaryKey: []*schema.Column{CarsColumns[0]},
+		ForeignKeys: []*schema.ForeignKey{
+			{
+				Symbol:  "cars_users_cars",
+				Columns: []*schema.Column{CarsColumns[3]},
+
+				RefColumns: []*schema.Column{UsersColumns[0]},
+				OnDelete:   schema.SetNull,
+			},
+		},
+	}
+	// GroupsColumns holds the columns for the "groups" table.
+	GroupsColumns = []*schema.Column{
+		{Name: "id", Type: field.TypeInt, Increment: true},
+		{Name: "name", Type: field.TypeString},
+	}
+	// GroupsTable holds the schema information for the "groups" table.
+	GroupsTable = &schema.Table{
+		Name:        "groups",
+		Columns:     GroupsColumns,
+		PrimaryKey:  []*schema.Column{GroupsColumns[0]},
+		ForeignKeys: []*schema.ForeignKey{},
+	}
+	// UsersColumns holds the columns for the "users" table.
+	UsersColumns = []*schema.Column{
+		{Name: "id", Type: field.TypeInt, Increment: true},
+		{Name: "age", Type: field.TypeInt},
+		{Name: "name", Type: field.TypeString, Default: user.DefaultName},
+	}
+	// UsersTable holds the schema information for the "users" table.
+	UsersTable = &schema.Table{
+		Name:        "users",
+		Columns:     UsersColumns,
+		PrimaryKey:  []*schema.Column{UsersColumns[0]},
+		ForeignKeys: []*schema.ForeignKey{},
+	}
+	// GroupUsersColumns holds the columns for the "group_users" table.
+	GroupUsersColumns = []*schema.Column{
+		{Name: "group_id", Type: field.TypeInt},
+		{Name: "user_id", Type: field.TypeInt},
+	}
+	// GroupUsersTable holds the schema information for the "group_users" table.
+	GroupUsersTable = &schema.Table{
+		Name:       "group_users",
+		Columns:    GroupUsersColumns,
+		PrimaryKey: []*schema.Column{GroupUsersColumns[0], GroupUsersColumns[1]},
+		ForeignKeys: []*schema.ForeignKey{
+			{
+				Symbol:  "group_users_group_id",
+				Columns: []*schema.Column{GroupUsersColumns[0]},
+
+				RefColumns: []*schema.Column{GroupsColumns[0]},
+				OnDelete:   schema.Cascade,
+			},
+			{
+				Symbol:  "group_users_user_id",
+				Columns: []*schema.Column{GroupUsersColumns[1]},
+
+				RefColumns: []*schema.Column{UsersColumns[0]},
+				OnDelete:   schema.Cascade,
+			},
+		},
+	}
+	// Tables holds all the tables in the schema.
+	Tables = []*schema.Table{
+		CarsTable,
+		GroupsTable,
+		UsersTable,
+		GroupUsersTable,
+	}
+)
+
+func init() {
+	CarsTable.ForeignKeys[0].RefTable = UsersTable
+	GroupUsersTable.ForeignKeys[0].RefTable = GroupsTable
+	GroupUsersTable.ForeignKeys[1].RefTable = UsersTable
+}

examples/start/ent/predicate/predicate.go

@@ -0,0 +1,20 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package predicate
+
+import (
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// Car is the predicate function for car builders.
+type Car func(*sql.Selector)
+
+// Group is the predicate function for group builders.
+type Group func(*sql.Selector)
+
+// User is the predicate function for user builders.
+type User func(*sql.Selector)

examples/start/ent/schema/car.go

@@ -0,0 +1,34 @@
+package schema
+
+import (
+	"github.com/facebookincubator/ent"
+	"github.com/facebookincubator/ent/schema/edge"
+	"github.com/facebookincubator/ent/schema/field"
+)
+
+// Car holds the schema definition for the Car entity.
+type Car struct {
+	ent.Schema
+}
+
+// Fields of the Car.
+func (Car) Fields() []ent.Field {
+	return []ent.Field{
+		field.String("model"),
+		field.Time("registered_at"),
+	}
+}
+
+// Edges of the Car.
+func (Car) Edges() []ent.Edge {
+	return []ent.Edge{
+		// create an inverse-edge called "owner" of type `User`
+		// and reference it to the "cars" edge (in User schema)
+		// explicitly using the `Ref` method.
+		edge.From("owner", User.Type).
+			Ref("cars").
+			// setting the edge to unique, ensure
+			// that a car can have only one owner.
+			Unique(),
+	}
+}

examples/start/ent/schema/group.go

@@ -0,0 +1,31 @@
+package schema
+
+import (
+	"regexp"
+
+	"github.com/facebookincubator/ent"
+	"github.com/facebookincubator/ent/schema/edge"
+	"github.com/facebookincubator/ent/schema/field"
+)
+
+// Group holds the schema definition for the Group entity.
+type Group struct {
+	ent.Schema
+}
+
+// Fields of the Group.
+// Fields of the Group.
+func (Group) Fields() []ent.Field {
+	return []ent.Field{
+		field.String("name").
+			// regexp validation for group name.
+			Match(regexp.MustCompile("[a-zA-Z_]+$")),
+	}
+}
+
+// Edges of the Group.
+func (Group) Edges() []ent.Edge {
+	return []ent.Edge{
+		edge.To("users", User.Type),
+	}
+}

examples/start/ent/schema/user.go

@@ -0,0 +1,34 @@
+package schema
+
+import (
+	"github.com/facebookincubator/ent"
+	"github.com/facebookincubator/ent/schema/edge"
+	"github.com/facebookincubator/ent/schema/field"
+)
+
+// User holds the schema definition for the User entity.
+type User struct {
+	ent.Schema
+}
+
+// Fields of the User.
+func (User) Fields() []ent.Field {
+	return []ent.Field{
+		field.Int("age").
+			Positive(),
+		field.String("name").
+			Default("unknown"),
+	}
+}
+
+// Edges of the User.
+func (User) Edges() []ent.Edge {
+	return []ent.Edge{
+		edge.To("cars", Car.Type),
+		// create an inverse-edge called "groups" of type `Group`
+		// and reference it to the "users" edge (in Group schema)
+		// explicitly using the `Ref` method.
+		edge.From("groups", Group.Type).
+			Ref("users"),
+	}
+}

examples/start/ent/tx.go

@@ -0,0 +1,103 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+
+	"github.com/facebookincubator/ent/dialect"
+	"github.com/facebookincubator/ent/examples/start/ent/migrate"
+)
+
+// Tx is a transactional client that is created by calling Client.Tx().
+type Tx struct {
+	config
+	// Car is the client for interacting with the Car builders.
+	Car *CarClient
+	// Group is the client for interacting with the Group builders.
+	Group *GroupClient
+	// User is the client for interacting with the User builders.
+	User *UserClient
+}
+
+// Commit commits the transaction.
+func (tx *Tx) Commit() error {
+	return tx.config.driver.(*txDriver).tx.Commit()
+}
+
+// Rollback rollbacks the transaction.
+func (tx *Tx) Rollback() error {
+	return tx.config.driver.(*txDriver).tx.Rollback()
+}
+
+// Client returns a Client that binds to current transaction.
+func (tx *Tx) Client() *Client {
+	return &Client{
+		config: tx.config,
+		Schema: migrate.NewSchema(tx.driver),
+		Car:    NewCarClient(tx.config),
+		Group:  NewGroupClient(tx.config),
+		User:   NewUserClient(tx.config),
+	}
+}
+
+// txDriver wraps the given dialect.Tx with a nop dialect.Driver implementation.
+// The idea is to support transactions without adding any extra code to the builders.
+// When a builder calls to driver.Tx(), it gets the same dialect.Tx instance.
+// Commit and Rollback are nop for the internal builders and the user must call one
+// of them in order to commit or rollback the transaction.
+//
+// If a closed transaction is embedded in one of the generated entities, and the entity
+// applies a query, for example: Car.QueryXXX(), the query will be executed
+// through the driver which created this transaction.
+//
+// Note that txDriver is not goroutine safe.
+type txDriver struct {
+	// the driver we started the transaction from.
+	drv dialect.Driver
+	// tx is the underlying transaction.
+	tx dialect.Tx
+}
+
+// newTx creates a new transactional driver.
+func newTx(ctx context.Context, drv dialect.Driver) (*txDriver, error) {
+	tx, err := drv.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	return &txDriver{tx: tx, drv: drv}, nil
+}
+
+// Tx returns the transaction wrapper (txDriver) to avoid Commit or Rollback calls
+// from the internal builders. Should be called only by the internal builders.
+func (tx *txDriver) Tx(context.Context) (dialect.Tx, error) { return tx, nil }
+
+// Dialect returns the dialect of the driver we started the transaction from.
+func (tx *txDriver) Dialect() string { return tx.drv.Dialect() }
+
+// Close is a nop close.
+func (*txDriver) Close() error { return nil }
+
+// Commit is a nop commit for the internal builders.
+// User must call `Tx.Commit` in order to commit the transaction.
+func (*txDriver) Commit() error { return nil }
+
+// Rollback is a nop rollback for the internal builders.
+// User must call `Tx.Rollback` in order to rollback the transaction.
+func (*txDriver) Rollback() error { return nil }
+
+// Exec calls tx.Exec.
+func (tx *txDriver) Exec(ctx context.Context, query string, args, v interface{}) error {
+	return tx.tx.Exec(ctx, query, args, v)
+}
+
+// Query calls tx.Query.
+func (tx *txDriver) Query(ctx context.Context, query string, args, v interface{}) error {
+	return tx.tx.Query(ctx, query, args, v)
+}
+
+var _ dialect.Driver = (*txDriver)(nil)

examples/start/ent/user.go

@@ -0,0 +1,106 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+)
+
+// User is the model entity for the User schema.
+type User struct {
+	config `json:"-"`
+	// ID of the ent.
+	ID int `json:"id,omitempty"`
+	// Age holds the value of the "age" field.
+	Age int `json:"age,omitempty"`
+	// Name holds the value of the "name" field.
+	Name string `json:"name,omitempty"`
+}
+
+// FromRows scans the sql response data into User.
+func (u *User) FromRows(rows *sql.Rows) error {
+	var vu struct {
+		ID   int
+		Age  sql.NullInt64
+		Name sql.NullString
+	}
+	// the order here should be the same as in the `user.Columns`.
+	if err := rows.Scan(
+		&vu.ID,
+		&vu.Age,
+		&vu.Name,
+	); err != nil {
+		return err
+	}
+	u.ID = vu.ID
+	u.Age = int(vu.Age.Int64)
+	u.Name = vu.Name.String
+	return nil
+}
+
+// QueryCars queries the cars edge of the User.
+func (u *User) QueryCars() *CarQuery {
+	return (&UserClient{u.config}).QueryCars(u)
+}
+
+// QueryGroups queries the groups edge of the User.
+func (u *User) QueryGroups() *GroupQuery {
+	return (&UserClient{u.config}).QueryGroups(u)
+}
+
+// Update returns a builder for updating this User.
+// Note that, you need to call User.Unwrap() before calling this method, if this User
+// was returned from a transaction, and the transaction was committed or rolled back.
+func (u *User) Update() *UserUpdateOne {
+	return (&UserClient{u.config}).UpdateOne(u)
+}
+
+// Unwrap unwraps the entity that was returned from a transaction after it was closed,
+// so that all next queries will be executed through the driver which created the transaction.
+func (u *User) Unwrap() *User {
+	tx, ok := u.config.driver.(*txDriver)
+	if !ok {
+		panic("ent: User is not a transactional entity")
+	}
+	u.config.driver = tx.drv
+	return u
+}
+
+// String implements the fmt.Stringer.
+func (u *User) String() string {
+	buf := bytes.NewBuffer(nil)
+	buf.WriteString("User(")
+	buf.WriteString(fmt.Sprintf("id=%v", u.ID))
+	buf.WriteString(fmt.Sprintf(", age=%v", u.Age))
+	buf.WriteString(fmt.Sprintf(", name=%v", u.Name))
+	buf.WriteString(")")
+	return buf.String()
+}
+
+// Users is a parsable slice of User.
+type Users []*User
+
+// FromRows scans the sql response data into Users.
+func (u *Users) FromRows(rows *sql.Rows) error {
+	for rows.Next() {
+		vu := &User{}
+		if err := vu.FromRows(rows); err != nil {
+			return err
+		}
+		*u = append(*u, vu)
+	}
+	return nil
+}
+
+func (u Users) config(cfg config) {
+	for i := range u {
+		u[i].config = cfg
+	}
+}

examples/start/ent/user/user.go

@@ -0,0 +1,64 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package user
+
+import (
+	"github.com/facebookincubator/ent/examples/start/ent/schema"
+)
+
+const (
+	// Label holds the string label denoting the user type in the database.
+	Label = "user"
+	// FieldID holds the string denoting the id field in the database.
+	FieldID = "id"
+	// FieldAge holds the string denoting the age vertex property in the database.
+	FieldAge = "age"
+	// FieldName holds the string denoting the name vertex property in the database.
+	FieldName = "name"
+
+	// Table holds the table name of the user in the database.
+	Table = "users"
+	// CarsTable is the table the holds the cars relation/edge.
+	CarsTable = "cars"
+	// CarsInverseTable is the table name for the Car entity.
+	// It exists in this package in order to avoid circular dependency with the "car" package.
+	CarsInverseTable = "cars"
+	// CarsColumn is the table column denoting the cars relation/edge.
+	CarsColumn = "owner_id"
+	// GroupsTable is the table the holds the groups relation/edge. The primary key declared below.
+	GroupsTable = "group_users"
+	// GroupsInverseTable is the table name for the Group entity.
+	// It exists in this package in order to avoid circular dependency with the "group" package.
+	GroupsInverseTable = "groups"
+)
+
+// Columns holds all SQL columns are user fields.
+var Columns = []string{
+	FieldID,
+	FieldAge,
+	FieldName,
+}
+
+var (
+	// GroupsPrimaryKey and GroupsColumn2 are the table columns denoting the
+	// primary key for the groups relation (M2M).
+	GroupsPrimaryKey = []string{"group_id", "user_id"}
+)
+
+var (
+	fields = schema.User{}.Fields()
+
+	// descAge is the schema descriptor for age field.
+	descAge = fields[0].Descriptor()
+	// AgeValidator is a validator for the "age" field. It is called by the builders before save.
+	AgeValidator = descAge.Validators[0].(func(int) error)
+
+	// descName is the schema descriptor for name field.
+	descName = fields[1].Descriptor()
+	// DefaultName holds the default value on creation for the name field.
+	DefaultName = descName.Default.(string)
+)

examples/start/ent/user/where.go

@@ -0,0 +1,461 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package user
+
+import (
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+)
+
+// ID filters vertices based on their identifier.
+func ID(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDEQ applies the EQ predicate on the ID field.
+func IDEQ(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDNEQ applies the NEQ predicate on the ID field.
+func IDNEQ(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDIn applies the In predicate on the ID field.
+func IDIn(ids ...int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(ids) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			v := make([]interface{}, len(ids))
+			for i := range v {
+				v[i] = ids[i]
+			}
+			s.Where(sql.In(s.C(FieldID), v...))
+		},
+	)
+}
+
+// IDNotIn applies the NotIn predicate on the ID field.
+func IDNotIn(ids ...int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(ids) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			v := make([]interface{}, len(ids))
+			for i := range v {
+				v[i] = ids[i]
+			}
+			s.Where(sql.NotIn(s.C(FieldID), v...))
+		},
+	)
+}
+
+// IDGT applies the GT predicate on the ID field.
+func IDGT(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDGTE applies the GTE predicate on the ID field.
+func IDGTE(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDLT applies the LT predicate on the ID field.
+func IDLT(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldID), id))
+		},
+	)
+}
+
+// IDLTE applies the LTE predicate on the ID field.
+func IDLTE(id int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldID), id))
+		},
+	)
+}
+
+// Age applies equality check predicate on the "age" field. It's identical to AgeEQ.
+func Age(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldAge), v))
+		},
+	)
+}
+
+// Name applies equality check predicate on the "name" field. It's identical to NameEQ.
+func Name(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldName), v))
+		},
+	)
+}
+
+// AgeEQ applies the EQ predicate on the "age" field.
+func AgeEQ(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldAge), v))
+		},
+	)
+}
+
+// AgeNEQ applies the NEQ predicate on the "age" field.
+func AgeNEQ(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldAge), v))
+		},
+	)
+}
+
+// AgeIn applies the In predicate on the "age" field.
+func AgeIn(vs ...int) predicate.User {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.User(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.In(s.C(FieldAge), v...))
+		},
+	)
+}
+
+// AgeNotIn applies the NotIn predicate on the "age" field.
+func AgeNotIn(vs ...int) predicate.User {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.User(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.NotIn(s.C(FieldAge), v...))
+		},
+	)
+}
+
+// AgeGT applies the GT predicate on the "age" field.
+func AgeGT(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldAge), v))
+		},
+	)
+}
+
+// AgeGTE applies the GTE predicate on the "age" field.
+func AgeGTE(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldAge), v))
+		},
+	)
+}
+
+// AgeLT applies the LT predicate on the "age" field.
+func AgeLT(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldAge), v))
+		},
+	)
+}
+
+// AgeLTE applies the LTE predicate on the "age" field.
+func AgeLTE(v int) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldAge), v))
+		},
+	)
+}
+
+// NameEQ applies the EQ predicate on the "name" field.
+func NameEQ(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EQ(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameNEQ applies the NEQ predicate on the "name" field.
+func NameNEQ(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.NEQ(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameIn applies the In predicate on the "name" field.
+func NameIn(vs ...string) predicate.User {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.User(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.In(s.C(FieldName), v...))
+		},
+	)
+}
+
+// NameNotIn applies the NotIn predicate on the "name" field.
+func NameNotIn(vs ...string) predicate.User {
+	v := make([]interface{}, len(vs))
+	for i := range v {
+		v[i] = vs[i]
+	}
+	return predicate.User(
+		func(s *sql.Selector) {
+			// if not arguments were provided, append the FALSE constants,
+			// since we can't apply "IN ()". This will make this predicate falsy.
+			if len(vs) == 0 {
+				s.Where(sql.False())
+				return
+			}
+			s.Where(sql.NotIn(s.C(FieldName), v...))
+		},
+	)
+}
+
+// NameGT applies the GT predicate on the "name" field.
+func NameGT(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.GT(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameGTE applies the GTE predicate on the "name" field.
+func NameGTE(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.GTE(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameLT applies the LT predicate on the "name" field.
+func NameLT(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.LT(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameLTE applies the LTE predicate on the "name" field.
+func NameLTE(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.LTE(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameContains applies the Contains predicate on the "name" field.
+func NameContains(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.Contains(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameHasPrefix applies the HasPrefix predicate on the "name" field.
+func NameHasPrefix(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.HasPrefix(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameHasSuffix applies the HasSuffix predicate on the "name" field.
+func NameHasSuffix(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.HasSuffix(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameEqualFold applies the EqualFold predicate on the "name" field.
+func NameEqualFold(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.EqualFold(s.C(FieldName), v))
+		},
+	)
+}
+
+// NameContainsFold applies the ContainsFold predicate on the "name" field.
+func NameContainsFold(v string) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			s.Where(sql.ContainsFold(s.C(FieldName), v))
+		},
+	)
+}
+
+// HasCars applies the HasEdge predicate on the "cars" edge.
+func HasCars() predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			s.Where(
+				sql.In(
+					t1.C(FieldID),
+					sql.Select(CarsColumn).
+						From(sql.Table(CarsTable)).
+						Where(sql.NotNull(CarsColumn)),
+				),
+			)
+		},
+	)
+}
+
+// HasCarsWith applies the HasEdge predicate on the "cars" edge with a given conditions (other predicates).
+func HasCarsWith(preds ...predicate.Car) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			t2 := sql.Select(CarsColumn).From(sql.Table(CarsTable))
+			for _, p := range preds {
+				p(t2)
+			}
+			s.Where(sql.In(t1.C(FieldID), t2))
+		},
+	)
+}
+
+// HasGroups applies the HasEdge predicate on the "groups" edge.
+func HasGroups() predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			s.Where(
+				sql.In(
+					t1.C(FieldID),
+					sql.Select(GroupsPrimaryKey[1]).From(sql.Table(GroupsTable)),
+				),
+			)
+		},
+	)
+}
+
+// HasGroupsWith applies the HasEdge predicate on the "groups" edge with a given conditions (other predicates).
+func HasGroupsWith(preds ...predicate.Group) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			t1 := s.Table()
+			t2 := sql.Table(GroupsInverseTable)
+			t3 := sql.Table(GroupsTable)
+			t4 := sql.Select(t3.C(GroupsPrimaryKey[1])).
+				From(t3).
+				Join(t2).
+				On(t3.C(GroupsPrimaryKey[0]), t2.C(FieldID))
+			t5 := sql.Select().From(t2)
+			for _, p := range preds {
+				p(t5)
+			}
+			t4.FromSelect(t5)
+			s.Where(sql.In(t1.C(FieldID), t4))
+		},
+	)
+}
+
+// And groups list of predicates with the AND operator between them.
+func And(predicates ...predicate.User) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			for _, p := range predicates {
+				p(s)
+			}
+		},
+	)
+}
+
+// Or groups list of predicates with the OR operator between them.
+func Or(predicates ...predicate.User) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			for i, p := range predicates {
+				if i > 0 {
+					s.Or()
+				}
+				p(s)
+			}
+		},
+	)
+}
+
+// Not applies the not operator on the given predicate.
+func Not(p predicate.User) predicate.User {
+	return predicate.User(
+		func(s *sql.Selector) {
+			p(s.Not())
+		},
+	)
+}

examples/start/ent/user_create.go

@@ -0,0 +1,175 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// UserCreate is the builder for creating a User entity.
+type UserCreate struct {
+	config
+	age    *int
+	name   *string
+	cars   map[int]struct{}
+	groups map[int]struct{}
+}
+
+// SetAge sets the age field.
+func (uc *UserCreate) SetAge(i int) *UserCreate {
+	uc.age = &i
+	return uc
+}
+
+// SetName sets the name field.
+func (uc *UserCreate) SetName(s string) *UserCreate {
+	uc.name = &s
+	return uc
+}
+
+// SetNillableName sets the name field if the given value is not nil.
+func (uc *UserCreate) SetNillableName(s *string) *UserCreate {
+	if s != nil {
+		uc.SetName(*s)
+	}
+	return uc
+}
+
+// AddCarIDs adds the cars edge to Car by ids.
+func (uc *UserCreate) AddCarIDs(ids ...int) *UserCreate {
+	if uc.cars == nil {
+		uc.cars = make(map[int]struct{})
+	}
+	for i := range ids {
+		uc.cars[ids[i]] = struct{}{}
+	}
+	return uc
+}
+
+// AddCars adds the cars edges to Car.
+func (uc *UserCreate) AddCars(c ...*Car) *UserCreate {
+	ids := make([]int, len(c))
+	for i := range c {
+		ids[i] = c[i].ID
+	}
+	return uc.AddCarIDs(ids...)
+}
+
+// AddGroupIDs adds the groups edge to Group by ids.
+func (uc *UserCreate) AddGroupIDs(ids ...int) *UserCreate {
+	if uc.groups == nil {
+		uc.groups = make(map[int]struct{})
+	}
+	for i := range ids {
+		uc.groups[ids[i]] = struct{}{}
+	}
+	return uc
+}
+
+// AddGroups adds the groups edges to Group.
+func (uc *UserCreate) AddGroups(g ...*Group) *UserCreate {
+	ids := make([]int, len(g))
+	for i := range g {
+		ids[i] = g[i].ID
+	}
+	return uc.AddGroupIDs(ids...)
+}
+
+// Save creates the User in the database.
+func (uc *UserCreate) Save(ctx context.Context) (*User, error) {
+	if uc.age == nil {
+		return nil, errors.New("ent: missing required field \"age\"")
+	}
+	if err := user.AgeValidator(*uc.age); err != nil {
+		return nil, fmt.Errorf("ent: validator failed for field \"age\": %v", err)
+	}
+	if uc.name == nil {
+		v := user.DefaultName
+		uc.name = &v
+	}
+	return uc.sqlSave(ctx)
+}
+
+// SaveX calls Save and panics if Save returns an error.
+func (uc *UserCreate) SaveX(ctx context.Context) *User {
+	v, err := uc.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (uc *UserCreate) sqlSave(ctx context.Context) (*User, error) {
+	var (
+		res sql.Result
+		u   = &User{config: uc.config}
+	)
+	tx, err := uc.driver.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	builder := sql.Insert(user.Table).Default(uc.driver.Dialect())
+	if value := uc.age; value != nil {
+		builder.Set(user.FieldAge, *value)
+		u.Age = *value
+	}
+	if value := uc.name; value != nil {
+		builder.Set(user.FieldName, *value)
+		u.Name = *value
+	}
+	query, args := builder.Query()
+	if err := tx.Exec(ctx, query, args, &res); err != nil {
+		return nil, rollback(tx, err)
+	}
+	id, err := res.LastInsertId()
+	if err != nil {
+		return nil, rollback(tx, err)
+	}
+	u.ID = int(id)
+	if len(uc.cars) > 0 {
+		p := sql.P()
+		for eid := range uc.cars {
+			p.Or().EQ(car.FieldID, eid)
+		}
+		query, args := sql.Update(user.CarsTable).
+			Set(user.CarsColumn, id).
+			Where(sql.And(p, sql.IsNull(user.CarsColumn))).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+		affected, err := res.RowsAffected()
+		if err != nil {
+			return nil, rollback(tx, err)
+		}
+		if int(affected) < len(uc.cars) {
+			return nil, rollback(tx, &ErrConstraintFailed{msg: fmt.Sprintf("one of \"cars\" %v already connected to a different \"User\"", keys(uc.cars))})
+		}
+	}
+	if len(uc.groups) > 0 {
+		for eid := range uc.groups {
+
+			query, args := sql.Insert(user.GroupsTable).
+				Columns(user.GroupsPrimaryKey[1], user.GroupsPrimaryKey[0]).
+				Values(id, eid).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return nil, rollback(tx, err)
+			}
+		}
+	}
+	if err := tx.Commit(); err != nil {
+		return nil, err
+	}
+	return u, nil
+}

examples/start/ent/user_delete.go

@@ -0,0 +1,81 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// UserDelete is the builder for deleting a User entity.
+type UserDelete struct {
+	config
+	predicates []predicate.User
+}
+
+// Where adds a new predicate to the delete builder.
+func (ud *UserDelete) Where(ps ...predicate.User) *UserDelete {
+	ud.predicates = append(ud.predicates, ps...)
+	return ud
+}
+
+// Exec executes the deletion query and returns how many vertices were deleted.
+func (ud *UserDelete) Exec(ctx context.Context) (int, error) {
+	return ud.sqlExec(ctx)
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (ud *UserDelete) ExecX(ctx context.Context) int {
+	n, err := ud.Exec(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return n
+}
+
+func (ud *UserDelete) sqlExec(ctx context.Context) (int, error) {
+	var res sql.Result
+	selector := sql.Select().From(sql.Table(user.Table))
+	for _, p := range ud.predicates {
+		p(selector)
+	}
+	query, args := sql.Delete(user.Table).FromSelect(selector).Query()
+	if err := ud.driver.Exec(ctx, query, args, &res); err != nil {
+		return 0, err
+	}
+	affected, err := res.RowsAffected()
+	if err != nil {
+		return 0, err
+	}
+	return int(affected), nil
+}
+
+// UserDeleteOne is the builder for deleting a single User entity.
+type UserDeleteOne struct {
+	ud *UserDelete
+}
+
+// Exec executes the deletion query.
+func (udo *UserDeleteOne) Exec(ctx context.Context) error {
+	n, err := udo.ud.Exec(ctx)
+	switch {
+	case err != nil:
+		return err
+	case n == 0:
+		return &ErrNotFound{user.Label}
+	default:
+		return nil
+	}
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (udo *UserDeleteOne) ExecX(ctx context.Context) {
+	udo.ud.ExecX(ctx)
+}

examples/start/ent/user_query.go

@@ -0,0 +1,629 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"math"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// UserQuery is the builder for querying User entities.
+type UserQuery struct {
+	config
+	limit      *int
+	offset     *int
+	order      []Order
+	unique     []string
+	predicates []predicate.User
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Where adds a new predicate for the builder.
+func (uq *UserQuery) Where(ps ...predicate.User) *UserQuery {
+	uq.predicates = append(uq.predicates, ps...)
+	return uq
+}
+
+// Limit adds a limit step to the query.
+func (uq *UserQuery) Limit(limit int) *UserQuery {
+	uq.limit = &limit
+	return uq
+}
+
+// Offset adds an offset step to the query.
+func (uq *UserQuery) Offset(offset int) *UserQuery {
+	uq.offset = &offset
+	return uq
+}
+
+// Order adds an order step to the query.
+func (uq *UserQuery) Order(o ...Order) *UserQuery {
+	uq.order = append(uq.order, o...)
+	return uq
+}
+
+// QueryCars chains the current query on the cars edge.
+func (uq *UserQuery) QueryCars() *CarQuery {
+	query := &CarQuery{config: uq.config}
+	t1 := sql.Table(car.Table)
+	t2 := uq.sqlQuery()
+	t2.Select(t2.C(user.FieldID))
+	query.sql = sql.Select().
+		From(t1).
+		Join(t2).
+		On(t1.C(user.CarsColumn), t2.C(user.FieldID))
+	return query
+}
+
+// QueryGroups chains the current query on the groups edge.
+func (uq *UserQuery) QueryGroups() *GroupQuery {
+	query := &GroupQuery{config: uq.config}
+	t1 := sql.Table(group.Table)
+	t2 := uq.sqlQuery()
+	t2.Select(t2.C(user.FieldID))
+	t3 := sql.Table(user.GroupsTable)
+	t4 := sql.Select(t3.C(user.GroupsPrimaryKey[0])).
+		From(t3).
+		Join(t2).
+		On(t3.C(user.GroupsPrimaryKey[1]), t2.C(user.FieldID))
+	query.sql = sql.Select().
+		From(t1).
+		Join(t4).
+		On(t1.C(group.FieldID), t4.C(user.GroupsPrimaryKey[0]))
+	return query
+}
+
+// First returns the first User entity in the query. Returns *ErrNotFound when no user was found.
+func (uq *UserQuery) First(ctx context.Context) (*User, error) {
+	us, err := uq.Limit(1).All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if len(us) == 0 {
+		return nil, &ErrNotFound{user.Label}
+	}
+	return us[0], nil
+}
+
+// FirstX is like First, but panics if an error occurs.
+func (uq *UserQuery) FirstX(ctx context.Context) *User {
+	u, err := uq.First(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return u
+}
+
+// FirstID returns the first User id in the query. Returns *ErrNotFound when no id was found.
+func (uq *UserQuery) FirstID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = uq.Limit(1).IDs(ctx); err != nil {
+		return
+	}
+	if len(ids) == 0 {
+		err = &ErrNotFound{user.Label}
+		return
+	}
+	return ids[0], nil
+}
+
+// FirstXID is like FirstID, but panics if an error occurs.
+func (uq *UserQuery) FirstXID(ctx context.Context) int {
+	id, err := uq.FirstID(ctx)
+	if err != nil && !IsNotFound(err) {
+		panic(err)
+	}
+	return id
+}
+
+// Only returns the only User entity in the query, returns an error if not exactly one entity was returned.
+func (uq *UserQuery) Only(ctx context.Context) (*User, error) {
+	us, err := uq.Limit(2).All(ctx)
+	if err != nil {
+		return nil, err
+	}
+	switch len(us) {
+	case 1:
+		return us[0], nil
+	case 0:
+		return nil, &ErrNotFound{user.Label}
+	default:
+		return nil, &ErrNotSingular{user.Label}
+	}
+}
+
+// OnlyX is like Only, but panics if an error occurs.
+func (uq *UserQuery) OnlyX(ctx context.Context) *User {
+	u, err := uq.Only(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}
+
+// OnlyID returns the only User id in the query, returns an error if not exactly one id was returned.
+func (uq *UserQuery) OnlyID(ctx context.Context) (id int, err error) {
+	var ids []int
+	if ids, err = uq.Limit(2).IDs(ctx); err != nil {
+		return
+	}
+	switch len(ids) {
+	case 1:
+		id = ids[0]
+	case 0:
+		err = &ErrNotFound{user.Label}
+	default:
+		err = &ErrNotSingular{user.Label}
+	}
+	return
+}
+
+// OnlyXID is like OnlyID, but panics if an error occurs.
+func (uq *UserQuery) OnlyXID(ctx context.Context) int {
+	id, err := uq.OnlyID(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return id
+}
+
+// All executes the query and returns a list of Users.
+func (uq *UserQuery) All(ctx context.Context) ([]*User, error) {
+	return uq.sqlAll(ctx)
+}
+
+// AllX is like All, but panics if an error occurs.
+func (uq *UserQuery) AllX(ctx context.Context) []*User {
+	us, err := uq.All(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return us
+}
+
+// IDs executes the query and returns a list of User ids.
+func (uq *UserQuery) IDs(ctx context.Context) ([]int, error) {
+	return uq.sqlIDs(ctx)
+}
+
+// IDsX is like IDs, but panics if an error occurs.
+func (uq *UserQuery) IDsX(ctx context.Context) []int {
+	ids, err := uq.IDs(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return ids
+}
+
+// Count returns the count of the given query.
+func (uq *UserQuery) Count(ctx context.Context) (int, error) {
+	return uq.sqlCount(ctx)
+}
+
+// CountX is like Count, but panics if an error occurs.
+func (uq *UserQuery) CountX(ctx context.Context) int {
+	count, err := uq.Count(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return count
+}
+
+// Exist returns true if the query has elements in the graph.
+func (uq *UserQuery) Exist(ctx context.Context) (bool, error) {
+	return uq.sqlExist(ctx)
+}
+
+// ExistX is like Exist, but panics if an error occurs.
+func (uq *UserQuery) ExistX(ctx context.Context) bool {
+	exist, err := uq.Exist(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return exist
+}
+
+// Clone returns a duplicate of the query builder, including all associated steps. It can be
+// used to prepare common query builders and use them differently after the clone is made.
+func (uq *UserQuery) Clone() *UserQuery {
+	return &UserQuery{
+		config:     uq.config,
+		limit:      uq.limit,
+		offset:     uq.offset,
+		order:      append([]Order{}, uq.order...),
+		unique:     append([]string{}, uq.unique...),
+		predicates: append([]predicate.User{}, uq.predicates...),
+		// clone intermediate queries.
+		sql: uq.sql.Clone(),
+	}
+}
+
+// GroupBy used to group vertices by one or more fields/columns.
+// It is often used with aggregate functions, like: count, max, mean, min, sum.
+//
+// Example:
+//
+//	var v []struct {
+//		Age int `json:"age,omitempty"`
+//		Count int `json:"count,omitempty"`
+//	}
+//
+//	client.User.Query().
+//		GroupBy(user.FieldAge).
+//		Aggregate(ent.Count()).
+//		Scan(ctx, &v)
+//
+func (uq *UserQuery) GroupBy(field string, fields ...string) *UserGroupBy {
+	group := &UserGroupBy{config: uq.config}
+	group.fields = append([]string{field}, fields...)
+	group.sql = uq.sqlQuery()
+	return group
+}
+
+// Select one or more fields from the given query.
+//
+// Example:
+//
+//	var v []struct {
+//		Age int `json:"age,omitempty"`
+//	}
+//
+//	client.User.Query().
+//		Select(user.FieldAge).
+//		Scan(ctx, &v)
+//
+func (uq *UserQuery) Select(field string, fields ...string) *UserSelect {
+	selector := &UserSelect{config: uq.config}
+	selector.fields = append([]string{field}, fields...)
+	selector.sql = uq.sqlQuery()
+	return selector
+}
+
+func (uq *UserQuery) sqlAll(ctx context.Context) ([]*User, error) {
+	rows := &sql.Rows{}
+	selector := uq.sqlQuery()
+	if unique := uq.unique; len(unique) == 0 {
+		selector.Distinct()
+	}
+	query, args := selector.Query()
+	if err := uq.driver.Query(ctx, query, args, rows); err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var us Users
+	if err := us.FromRows(rows); err != nil {
+		return nil, err
+	}
+	us.config(uq.config)
+	return us, nil
+}
+
+func (uq *UserQuery) sqlCount(ctx context.Context) (int, error) {
+	rows := &sql.Rows{}
+	selector := uq.sqlQuery()
+	unique := []string{user.FieldID}
+	if len(uq.unique) > 0 {
+		unique = uq.unique
+	}
+	selector.Count(sql.Distinct(selector.Columns(unique...)...))
+	query, args := selector.Query()
+	if err := uq.driver.Query(ctx, query, args, rows); err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+	if !rows.Next() {
+		return 0, errors.New("ent: no rows found")
+	}
+	var n int
+	if err := rows.Scan(&n); err != nil {
+		return 0, fmt.Errorf("ent: failed reading count: %v", err)
+	}
+	return n, nil
+}
+
+func (uq *UserQuery) sqlExist(ctx context.Context) (bool, error) {
+	n, err := uq.sqlCount(ctx)
+	if err != nil {
+		return false, fmt.Errorf("ent: check existence: %v", err)
+	}
+	return n > 0, nil
+}
+
+func (uq *UserQuery) sqlIDs(ctx context.Context) ([]int, error) {
+	vs, err := uq.sqlAll(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var ids []int
+	for _, v := range vs {
+		ids = append(ids, v.ID)
+	}
+	return ids, nil
+}
+
+func (uq *UserQuery) sqlQuery() *sql.Selector {
+	t1 := sql.Table(user.Table)
+	selector := sql.Select(t1.Columns(user.Columns...)...).From(t1)
+	if uq.sql != nil {
+		selector = uq.sql
+		selector.Select(selector.Columns(user.Columns...)...)
+	}
+	for _, p := range uq.predicates {
+		p(selector)
+	}
+	for _, p := range uq.order {
+		p(selector)
+	}
+	if offset := uq.offset; offset != nil {
+		// limit is mandatory for offset clause. We start
+		// with default value, and override it below if needed.
+		selector.Offset(*offset).Limit(math.MaxInt64)
+	}
+	if limit := uq.limit; limit != nil {
+		selector.Limit(*limit)
+	}
+	return selector
+}
+
+// UserGroupBy is the builder for group-by User entities.
+type UserGroupBy struct {
+	config
+	fields []string
+	fns    []Aggregate
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Aggregate adds the given aggregation functions to the group-by query.
+func (ugb *UserGroupBy) Aggregate(fns ...Aggregate) *UserGroupBy {
+	ugb.fns = append(ugb.fns, fns...)
+	return ugb
+}
+
+// Scan applies the group-by query and scan the result into the given value.
+func (ugb *UserGroupBy) Scan(ctx context.Context, v interface{}) error {
+	return ugb.sqlScan(ctx, v)
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (ugb *UserGroupBy) ScanX(ctx context.Context, v interface{}) {
+	if err := ugb.Scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from group-by. It is only allowed when querying group-by with one field.
+func (ugb *UserGroupBy) Strings(ctx context.Context) ([]string, error) {
+	if len(ugb.fields) > 1 {
+		return nil, errors.New("ent: UserGroupBy.Strings is not achievable when grouping more than 1 field")
+	}
+	var v []string
+	if err := ugb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (ugb *UserGroupBy) StringsX(ctx context.Context) []string {
+	v, err := ugb.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from group-by. It is only allowed when querying group-by with one field.
+func (ugb *UserGroupBy) Ints(ctx context.Context) ([]int, error) {
+	if len(ugb.fields) > 1 {
+		return nil, errors.New("ent: UserGroupBy.Ints is not achievable when grouping more than 1 field")
+	}
+	var v []int
+	if err := ugb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (ugb *UserGroupBy) IntsX(ctx context.Context) []int {
+	v, err := ugb.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from group-by. It is only allowed when querying group-by with one field.
+func (ugb *UserGroupBy) Float64s(ctx context.Context) ([]float64, error) {
+	if len(ugb.fields) > 1 {
+		return nil, errors.New("ent: UserGroupBy.Float64s is not achievable when grouping more than 1 field")
+	}
+	var v []float64
+	if err := ugb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (ugb *UserGroupBy) Float64sX(ctx context.Context) []float64 {
+	v, err := ugb.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from group-by. It is only allowed when querying group-by with one field.
+func (ugb *UserGroupBy) Bools(ctx context.Context) ([]bool, error) {
+	if len(ugb.fields) > 1 {
+		return nil, errors.New("ent: UserGroupBy.Bools is not achievable when grouping more than 1 field")
+	}
+	var v []bool
+	if err := ugb.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (ugb *UserGroupBy) BoolsX(ctx context.Context) []bool {
+	v, err := ugb.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (ugb *UserGroupBy) sqlScan(ctx context.Context, v interface{}) error {
+	rows := &sql.Rows{}
+	query, args := ugb.sqlQuery().Query()
+	if err := ugb.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+func (ugb *UserGroupBy) sqlQuery() *sql.Selector {
+	selector := ugb.sql
+	columns := make([]string, 0, len(ugb.fields)+len(ugb.fns))
+	columns = append(columns, ugb.fields...)
+	for _, fn := range ugb.fns {
+		columns = append(columns, fn.SQL(selector))
+	}
+	return selector.Select(columns...).GroupBy(ugb.fields...)
+}
+
+// UserSelect is the builder for select fields of User entities.
+type UserSelect struct {
+	config
+	fields []string
+	// intermediate queries.
+	sql *sql.Selector
+}
+
+// Scan applies the selector query and scan the result into the given value.
+func (us *UserSelect) Scan(ctx context.Context, v interface{}) error {
+	return us.sqlScan(ctx, v)
+}
+
+// ScanX is like Scan, but panics if an error occurs.
+func (us *UserSelect) ScanX(ctx context.Context, v interface{}) {
+	if err := us.Scan(ctx, v); err != nil {
+		panic(err)
+	}
+}
+
+// Strings returns list of strings from selector. It is only allowed when selecting one field.
+func (us *UserSelect) Strings(ctx context.Context) ([]string, error) {
+	if len(us.fields) > 1 {
+		return nil, errors.New("ent: UserSelect.Strings is not achievable when selecting more than 1 field")
+	}
+	var v []string
+	if err := us.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// StringsX is like Strings, but panics if an error occurs.
+func (us *UserSelect) StringsX(ctx context.Context) []string {
+	v, err := us.Strings(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Ints returns list of ints from selector. It is only allowed when selecting one field.
+func (us *UserSelect) Ints(ctx context.Context) ([]int, error) {
+	if len(us.fields) > 1 {
+		return nil, errors.New("ent: UserSelect.Ints is not achievable when selecting more than 1 field")
+	}
+	var v []int
+	if err := us.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// IntsX is like Ints, but panics if an error occurs.
+func (us *UserSelect) IntsX(ctx context.Context) []int {
+	v, err := us.Ints(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Float64s returns list of float64s from selector. It is only allowed when selecting one field.
+func (us *UserSelect) Float64s(ctx context.Context) ([]float64, error) {
+	if len(us.fields) > 1 {
+		return nil, errors.New("ent: UserSelect.Float64s is not achievable when selecting more than 1 field")
+	}
+	var v []float64
+	if err := us.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// Float64sX is like Float64s, but panics if an error occurs.
+func (us *UserSelect) Float64sX(ctx context.Context) []float64 {
+	v, err := us.Float64s(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Bools returns list of bools from selector. It is only allowed when selecting one field.
+func (us *UserSelect) Bools(ctx context.Context) ([]bool, error) {
+	if len(us.fields) > 1 {
+		return nil, errors.New("ent: UserSelect.Bools is not achievable when selecting more than 1 field")
+	}
+	var v []bool
+	if err := us.Scan(ctx, &v); err != nil {
+		return nil, err
+	}
+	return v, nil
+}
+
+// BoolsX is like Bools, but panics if an error occurs.
+func (us *UserSelect) BoolsX(ctx context.Context) []bool {
+	v, err := us.Bools(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+func (us *UserSelect) sqlScan(ctx context.Context, v interface{}) error {
+	rows := &sql.Rows{}
+	query, args := us.sqlQuery().Query()
+	if err := us.driver.Query(ctx, query, args, rows); err != nil {
+		return err
+	}
+	defer rows.Close()
+	return sql.ScanSlice(rows, v)
+}
+
+func (us *UserSelect) sqlQuery() sql.Querier {
+	view := "user_view"
+	return sql.Select(us.fields...).From(us.sql.As(view))
+}

examples/start/ent/user_update.go

@@ -0,0 +1,577 @@
+// Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+// Code generated (@generated) by entc, DO NOT EDIT.
+
+package ent
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/facebookincubator/ent/dialect/sql"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/predicate"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+)
+
+// UserUpdate is the builder for updating User entities.
+type UserUpdate struct {
+	config
+	age           *int
+	addage        *int
+	name          *string
+	cars          map[int]struct{}
+	groups        map[int]struct{}
+	removedCars   map[int]struct{}
+	removedGroups map[int]struct{}
+	predicates    []predicate.User
+}
+
+// Where adds a new predicate for the builder.
+func (uu *UserUpdate) Where(ps ...predicate.User) *UserUpdate {
+	uu.predicates = append(uu.predicates, ps...)
+	return uu
+}
+
+// SetAge sets the age field.
+func (uu *UserUpdate) SetAge(i int) *UserUpdate {
+	uu.age = &i
+	uu.addage = nil
+	return uu
+}
+
+// AddAge adds i to age.
+func (uu *UserUpdate) AddAge(i int) *UserUpdate {
+	if uu.addage == nil {
+		uu.addage = &i
+	} else {
+		*uu.addage += i
+	}
+	return uu
+}
+
+// SetName sets the name field.
+func (uu *UserUpdate) SetName(s string) *UserUpdate {
+	uu.name = &s
+	return uu
+}
+
+// SetNillableName sets the name field if the given value is not nil.
+func (uu *UserUpdate) SetNillableName(s *string) *UserUpdate {
+	if s != nil {
+		uu.SetName(*s)
+	}
+	return uu
+}
+
+// AddCarIDs adds the cars edge to Car by ids.
+func (uu *UserUpdate) AddCarIDs(ids ...int) *UserUpdate {
+	if uu.cars == nil {
+		uu.cars = make(map[int]struct{})
+	}
+	for i := range ids {
+		uu.cars[ids[i]] = struct{}{}
+	}
+	return uu
+}
+
+// AddCars adds the cars edges to Car.
+func (uu *UserUpdate) AddCars(c ...*Car) *UserUpdate {
+	ids := make([]int, len(c))
+	for i := range c {
+		ids[i] = c[i].ID
+	}
+	return uu.AddCarIDs(ids...)
+}
+
+// AddGroupIDs adds the groups edge to Group by ids.
+func (uu *UserUpdate) AddGroupIDs(ids ...int) *UserUpdate {
+	if uu.groups == nil {
+		uu.groups = make(map[int]struct{})
+	}
+	for i := range ids {
+		uu.groups[ids[i]] = struct{}{}
+	}
+	return uu
+}
+
+// AddGroups adds the groups edges to Group.
+func (uu *UserUpdate) AddGroups(g ...*Group) *UserUpdate {
+	ids := make([]int, len(g))
+	for i := range g {
+		ids[i] = g[i].ID
+	}
+	return uu.AddGroupIDs(ids...)
+}
+
+// RemoveCarIDs removes the cars edge to Car by ids.
+func (uu *UserUpdate) RemoveCarIDs(ids ...int) *UserUpdate {
+	if uu.removedCars == nil {
+		uu.removedCars = make(map[int]struct{})
+	}
+	for i := range ids {
+		uu.removedCars[ids[i]] = struct{}{}
+	}
+	return uu
+}
+
+// RemoveCars removes cars edges to Car.
+func (uu *UserUpdate) RemoveCars(c ...*Car) *UserUpdate {
+	ids := make([]int, len(c))
+	for i := range c {
+		ids[i] = c[i].ID
+	}
+	return uu.RemoveCarIDs(ids...)
+}
+
+// RemoveGroupIDs removes the groups edge to Group by ids.
+func (uu *UserUpdate) RemoveGroupIDs(ids ...int) *UserUpdate {
+	if uu.removedGroups == nil {
+		uu.removedGroups = make(map[int]struct{})
+	}
+	for i := range ids {
+		uu.removedGroups[ids[i]] = struct{}{}
+	}
+	return uu
+}
+
+// RemoveGroups removes groups edges to Group.
+func (uu *UserUpdate) RemoveGroups(g ...*Group) *UserUpdate {
+	ids := make([]int, len(g))
+	for i := range g {
+		ids[i] = g[i].ID
+	}
+	return uu.RemoveGroupIDs(ids...)
+}
+
+// Save executes the query and returns the number of rows/vertices matched by this operation.
+func (uu *UserUpdate) Save(ctx context.Context) (int, error) {
+	if uu.age != nil {
+		if err := user.AgeValidator(*uu.age); err != nil {
+			return 0, fmt.Errorf("ent: validator failed for field \"age\": %v", err)
+		}
+	}
+	return uu.sqlSave(ctx)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (uu *UserUpdate) SaveX(ctx context.Context) int {
+	affected, err := uu.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return affected
+}
+
+// Exec executes the query.
+func (uu *UserUpdate) Exec(ctx context.Context) error {
+	_, err := uu.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (uu *UserUpdate) ExecX(ctx context.Context) {
+	if err := uu.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (uu *UserUpdate) sqlSave(ctx context.Context) (n int, err error) {
+	selector := sql.Select(user.FieldID).From(sql.Table(user.Table))
+	for _, p := range uu.predicates {
+		p(selector)
+	}
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err = uu.driver.Query(ctx, query, args, rows); err != nil {
+		return 0, err
+	}
+	defer rows.Close()
+	var ids []int
+	for rows.Next() {
+		var id int
+		if err := rows.Scan(&id); err != nil {
+			return 0, fmt.Errorf("ent: failed reading id: %v", err)
+		}
+		ids = append(ids, id)
+	}
+	if len(ids) == 0 {
+		return 0, nil
+	}
+
+	tx, err := uu.driver.Tx(ctx)
+	if err != nil {
+		return 0, err
+	}
+	var (
+		res     sql.Result
+		builder = sql.Update(user.Table).Where(sql.InInts(user.FieldID, ids...))
+	)
+	if value := uu.age; value != nil {
+		builder.Set(user.FieldAge, *value)
+	}
+	if value := uu.addage; value != nil {
+		builder.Add(user.FieldAge, *value)
+	}
+	if value := uu.name; value != nil {
+		builder.Set(user.FieldName, *value)
+	}
+	if !builder.Empty() {
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if len(uu.removedCars) > 0 {
+		eids := make([]int, len(uu.removedCars))
+		for eid := range uu.removedCars {
+			eids = append(eids, eid)
+		}
+		query, args := sql.Update(user.CarsTable).
+			SetNull(user.CarsColumn).
+			Where(sql.InInts(user.CarsColumn, ids...)).
+			Where(sql.InInts(car.FieldID, eids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if len(uu.cars) > 0 {
+		for _, id := range ids {
+			p := sql.P()
+			for eid := range uu.cars {
+				p.Or().EQ(car.FieldID, eid)
+			}
+			query, args := sql.Update(user.CarsTable).
+				Set(user.CarsColumn, id).
+				Where(sql.And(p, sql.IsNull(user.CarsColumn))).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return 0, rollback(tx, err)
+			}
+			affected, err := res.RowsAffected()
+			if err != nil {
+				return 0, rollback(tx, err)
+			}
+			if int(affected) < len(uu.cars) {
+				return 0, rollback(tx, &ErrConstraintFailed{msg: fmt.Sprintf("one of \"cars\" %v already connected to a different \"User\"", keys(uu.cars))})
+			}
+		}
+	}
+	if len(uu.removedGroups) > 0 {
+		eids := make([]int, len(uu.removedGroups))
+		for eid := range uu.removedGroups {
+			eids = append(eids, eid)
+		}
+		query, args := sql.Delete(user.GroupsTable).
+			Where(sql.InInts(user.GroupsPrimaryKey[1], ids...)).
+			Where(sql.InInts(user.GroupsPrimaryKey[0], eids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if len(uu.groups) > 0 {
+		values := make([][]int, 0, len(ids))
+		for _, id := range ids {
+			for eid := range uu.groups {
+				values = append(values, []int{id, eid})
+			}
+		}
+		builder := sql.Insert(user.GroupsTable).
+			Columns(user.GroupsPrimaryKey[1], user.GroupsPrimaryKey[0])
+		for _, v := range values {
+			builder.Values(v[0], v[1])
+		}
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return 0, rollback(tx, err)
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return 0, err
+	}
+	return len(ids), nil
+}
+
+// UserUpdateOne is the builder for updating a single User entity.
+type UserUpdateOne struct {
+	config
+	id            int
+	age           *int
+	addage        *int
+	name          *string
+	cars          map[int]struct{}
+	groups        map[int]struct{}
+	removedCars   map[int]struct{}
+	removedGroups map[int]struct{}
+}
+
+// SetAge sets the age field.
+func (uuo *UserUpdateOne) SetAge(i int) *UserUpdateOne {
+	uuo.age = &i
+	uuo.addage = nil
+	return uuo
+}
+
+// AddAge adds i to age.
+func (uuo *UserUpdateOne) AddAge(i int) *UserUpdateOne {
+	if uuo.addage == nil {
+		uuo.addage = &i
+	} else {
+		*uuo.addage += i
+	}
+	return uuo
+}
+
+// SetName sets the name field.
+func (uuo *UserUpdateOne) SetName(s string) *UserUpdateOne {
+	uuo.name = &s
+	return uuo
+}
+
+// SetNillableName sets the name field if the given value is not nil.
+func (uuo *UserUpdateOne) SetNillableName(s *string) *UserUpdateOne {
+	if s != nil {
+		uuo.SetName(*s)
+	}
+	return uuo
+}
+
+// AddCarIDs adds the cars edge to Car by ids.
+func (uuo *UserUpdateOne) AddCarIDs(ids ...int) *UserUpdateOne {
+	if uuo.cars == nil {
+		uuo.cars = make(map[int]struct{})
+	}
+	for i := range ids {
+		uuo.cars[ids[i]] = struct{}{}
+	}
+	return uuo
+}
+
+// AddCars adds the cars edges to Car.
+func (uuo *UserUpdateOne) AddCars(c ...*Car) *UserUpdateOne {
+	ids := make([]int, len(c))
+	for i := range c {
+		ids[i] = c[i].ID
+	}
+	return uuo.AddCarIDs(ids...)
+}
+
+// AddGroupIDs adds the groups edge to Group by ids.
+func (uuo *UserUpdateOne) AddGroupIDs(ids ...int) *UserUpdateOne {
+	if uuo.groups == nil {
+		uuo.groups = make(map[int]struct{})
+	}
+	for i := range ids {
+		uuo.groups[ids[i]] = struct{}{}
+	}
+	return uuo
+}
+
+// AddGroups adds the groups edges to Group.
+func (uuo *UserUpdateOne) AddGroups(g ...*Group) *UserUpdateOne {
+	ids := make([]int, len(g))
+	for i := range g {
+		ids[i] = g[i].ID
+	}
+	return uuo.AddGroupIDs(ids...)
+}
+
+// RemoveCarIDs removes the cars edge to Car by ids.
+func (uuo *UserUpdateOne) RemoveCarIDs(ids ...int) *UserUpdateOne {
+	if uuo.removedCars == nil {
+		uuo.removedCars = make(map[int]struct{})
+	}
+	for i := range ids {
+		uuo.removedCars[ids[i]] = struct{}{}
+	}
+	return uuo
+}
+
+// RemoveCars removes cars edges to Car.
+func (uuo *UserUpdateOne) RemoveCars(c ...*Car) *UserUpdateOne {
+	ids := make([]int, len(c))
+	for i := range c {
+		ids[i] = c[i].ID
+	}
+	return uuo.RemoveCarIDs(ids...)
+}
+
+// RemoveGroupIDs removes the groups edge to Group by ids.
+func (uuo *UserUpdateOne) RemoveGroupIDs(ids ...int) *UserUpdateOne {
+	if uuo.removedGroups == nil {
+		uuo.removedGroups = make(map[int]struct{})
+	}
+	for i := range ids {
+		uuo.removedGroups[ids[i]] = struct{}{}
+	}
+	return uuo
+}
+
+// RemoveGroups removes groups edges to Group.
+func (uuo *UserUpdateOne) RemoveGroups(g ...*Group) *UserUpdateOne {
+	ids := make([]int, len(g))
+	for i := range g {
+		ids[i] = g[i].ID
+	}
+	return uuo.RemoveGroupIDs(ids...)
+}
+
+// Save executes the query and returns the updated entity.
+func (uuo *UserUpdateOne) Save(ctx context.Context) (*User, error) {
+	if uuo.age != nil {
+		if err := user.AgeValidator(*uuo.age); err != nil {
+			return nil, fmt.Errorf("ent: validator failed for field \"age\": %v", err)
+		}
+	}
+	return uuo.sqlSave(ctx)
+}
+
+// SaveX is like Save, but panics if an error occurs.
+func (uuo *UserUpdateOne) SaveX(ctx context.Context) *User {
+	u, err := uuo.Save(ctx)
+	if err != nil {
+		panic(err)
+	}
+	return u
+}
+
+// Exec executes the query on the entity.
+func (uuo *UserUpdateOne) Exec(ctx context.Context) error {
+	_, err := uuo.Save(ctx)
+	return err
+}
+
+// ExecX is like Exec, but panics if an error occurs.
+func (uuo *UserUpdateOne) ExecX(ctx context.Context) {
+	if err := uuo.Exec(ctx); err != nil {
+		panic(err)
+	}
+}
+
+func (uuo *UserUpdateOne) sqlSave(ctx context.Context) (u *User, err error) {
+	selector := sql.Select(user.Columns...).From(sql.Table(user.Table))
+	user.ID(uuo.id)(selector)
+	rows := &sql.Rows{}
+	query, args := selector.Query()
+	if err = uuo.driver.Query(ctx, query, args, rows); err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	var ids []int
+	for rows.Next() {
+		var id int
+		u = &User{config: uuo.config}
+		if err := u.FromRows(rows); err != nil {
+			return nil, fmt.Errorf("ent: failed scanning row into User: %v", err)
+		}
+		id = u.ID
+		ids = append(ids, id)
+	}
+	switch n := len(ids); {
+	case n == 0:
+		return nil, fmt.Errorf("ent: User not found with id: %v", uuo.id)
+	case n > 1:
+		return nil, fmt.Errorf("ent: more than one User with the same id: %v", uuo.id)
+	}
+
+	tx, err := uuo.driver.Tx(ctx)
+	if err != nil {
+		return nil, err
+	}
+	var (
+		res     sql.Result
+		builder = sql.Update(user.Table).Where(sql.InInts(user.FieldID, ids...))
+	)
+	if value := uuo.age; value != nil {
+		builder.Set(user.FieldAge, *value)
+		u.Age = *value
+	}
+	if value := uuo.addage; value != nil {
+		builder.Add(user.FieldAge, *value)
+		u.Age += *value
+	}
+	if value := uuo.name; value != nil {
+		builder.Set(user.FieldName, *value)
+		u.Name = *value
+	}
+	if !builder.Empty() {
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if len(uuo.removedCars) > 0 {
+		eids := make([]int, len(uuo.removedCars))
+		for eid := range uuo.removedCars {
+			eids = append(eids, eid)
+		}
+		query, args := sql.Update(user.CarsTable).
+			SetNull(user.CarsColumn).
+			Where(sql.InInts(user.CarsColumn, ids...)).
+			Where(sql.InInts(car.FieldID, eids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if len(uuo.cars) > 0 {
+		for _, id := range ids {
+			p := sql.P()
+			for eid := range uuo.cars {
+				p.Or().EQ(car.FieldID, eid)
+			}
+			query, args := sql.Update(user.CarsTable).
+				Set(user.CarsColumn, id).
+				Where(sql.And(p, sql.IsNull(user.CarsColumn))).
+				Query()
+			if err := tx.Exec(ctx, query, args, &res); err != nil {
+				return nil, rollback(tx, err)
+			}
+			affected, err := res.RowsAffected()
+			if err != nil {
+				return nil, rollback(tx, err)
+			}
+			if int(affected) < len(uuo.cars) {
+				return nil, rollback(tx, &ErrConstraintFailed{msg: fmt.Sprintf("one of \"cars\" %v already connected to a different \"User\"", keys(uuo.cars))})
+			}
+		}
+	}
+	if len(uuo.removedGroups) > 0 {
+		eids := make([]int, len(uuo.removedGroups))
+		for eid := range uuo.removedGroups {
+			eids = append(eids, eid)
+		}
+		query, args := sql.Delete(user.GroupsTable).
+			Where(sql.InInts(user.GroupsPrimaryKey[1], ids...)).
+			Where(sql.InInts(user.GroupsPrimaryKey[0], eids...)).
+			Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if len(uuo.groups) > 0 {
+		values := make([][]int, 0, len(ids))
+		for _, id := range ids {
+			for eid := range uuo.groups {
+				values = append(values, []int{id, eid})
+			}
+		}
+		builder := sql.Insert(user.GroupsTable).
+			Columns(user.GroupsPrimaryKey[1], user.GroupsPrimaryKey[0])
+		for _, v := range values {
+			builder.Values(v[0], v[1])
+		}
+		query, args := builder.Query()
+		if err := tx.Exec(ctx, query, args, &res); err != nil {
+			return nil, rollback(tx, err)
+		}
+	}
+	if err = tx.Commit(); err != nil {
+		return nil, err
+	}
+	return u, nil
+}

examples/start/start.go

@@ -0,0 +1,279 @@
+// Copyright 2019-present Facebook Inc. All rights reserved.
+// This source code is licensed under the Apache 2.0 license found
+// in the LICENSE file in the root directory of this source tree.
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/facebookincubator/ent/examples/start/ent"
+	"github.com/facebookincubator/ent/examples/start/ent/car"
+	"github.com/facebookincubator/ent/examples/start/ent/group"
+	"github.com/facebookincubator/ent/examples/start/ent/user"
+
+	_ "github.com/mattn/go-sqlite3"
+)
+
+func main() {
+	client, err := ent.Open("sqlite3", "file:ent?mode=memory&cache=shared&_fk=1")
+	if err != nil {
+		log.Fatalf("failed opening connection to sqlite: %v", err)
+	}
+	defer client.Close()
+	ctx := context.Background()
+	// run the auto migration tool.
+	if err := client.Schema.Create(ctx); err != nil {
+		log.Fatalf("failed creating schema resources: %v", err)
+	}
+	if _, err = CreateUser(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if _, err = QueryUser(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	a8m, err := CreateCars(ctx, client)
+	if err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryCars(ctx, a8m); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryCarUsers(ctx, a8m); err != nil {
+		log.Fatal(err)
+	}
+	if err := CreateGraph(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryGithub(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryArielCars(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+	if err := QueryGroupWithUsers(ctx, client); err != nil {
+		log.Fatal(err)
+	}
+}
+
+func CreateUser(ctx context.Context, client *ent.Client) (*ent.User, error) {
+	u, err := client.User.
+		Create().
+		SetAge(30).
+		SetName("a8m").
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating user: %v", err)
+	}
+	log.Println("user was created: ", u)
+	return u, nil
+}
+
+func QueryUser(ctx context.Context, client *ent.Client) (*ent.User, error) {
+	u, err := client.User.
+		Query().
+		Where(user.NameEQ("a8m")).
+		// `Only` fails if no user found,
+		// or more than 1 user returned.
+		Only(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed querying user: %v", err)
+	}
+	log.Println("user returned: ", u)
+	return u, nil
+}
+
+func CreateCars(ctx context.Context, client *ent.Client) (*ent.User, error) {
+	// creating new car with model "Tesla".
+	tesla, err := client.Car.
+		Create().
+		SetModel("Tesla").
+		SetRegisteredAt(time.Now()).
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating car: %v", err)
+	}
+
+	// creating new car with model "Ford".
+	ford, err := client.Car.
+		Create().
+		SetModel("Ford").
+		SetRegisteredAt(time.Now()).
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating car: %v", err)
+	}
+	log.Println("car was created: ", ford)
+
+	// create a new user, and add it the 2 cars.
+	a8m, err := client.User.
+		Create().
+		SetAge(30).
+		SetName("a8m").
+		AddCars(tesla, ford).
+		Save(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed creating user: %v", err)
+	}
+	log.Println("user was created: ", a8m)
+	return a8m, nil
+}
+
+func QueryCars(ctx context.Context, a8m *ent.User) error {
+	cars, err := a8m.QueryCars().All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed querying user cars: %v", err)
+	}
+	log.Println("returned cars:", cars)
+
+	// what about filtering specific cars.
+	ford, err := a8m.QueryCars().
+		Where(car.ModelEQ("Ford")).
+		Only(ctx)
+	if err != nil {
+		return fmt.Errorf("failed querying user cars: %v", err)
+	}
+	log.Println(ford)
+	return nil
+}
+
+func QueryCarUsers(ctx context.Context, a8m *ent.User) error {
+	cars, err := a8m.QueryCars().All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed querying user cars: %v", err)
+	}
+
+	// query the inverse edge.
+	for _, ca := range cars {
+		owner, err := ca.QueryOwner().Only(ctx)
+		if err != nil {
+			return fmt.Errorf("failed querying car %q owner: %v", ca.Model, err)
+		}
+		log.Printf("car %q owner: %q\n", ca.Model, owner.Name)
+	}
+	return nil
+}
+
+func CreateGraph(ctx context.Context, client *ent.Client) error {
+	// first, create the users.
+	a8m, err := client.User.
+		Create().
+		SetAge(30).
+		SetName("Ariel").
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	neta, err := client.User.
+		Create().
+		SetAge(28).
+		SetName("Neta").
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	// then, create the cars, and attach them to the users in the creation.
+	_, err = client.Car.
+		Create().
+		SetModel("Tesla").
+		SetRegisteredAt(time.Now()). // ignore the time in the graph.
+		SetOwner(a8m).               // attach this graph to Ariel.
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	_, err = client.Car.
+		Create().
+		SetModel("Mazda").
+		SetRegisteredAt(time.Now()). // ignore the time in the graph.
+		SetOwner(a8m).               // attach this graph to Ariel.
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	_, err = client.Car.
+		Create().
+		SetModel("Ford").
+		SetRegisteredAt(time.Now()). // ignore the time in the graph.
+		SetOwner(neta).              // attach this graph to Neta.
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	// create the groups, and add their users in the creation.
+	_, err = client.Group.
+		Create().
+		SetName("GitLab").
+		AddUsers(neta, a8m).
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	_, err = client.Group.
+		Create().
+		SetName("GitHub").
+		AddUsers(a8m).
+		Save(ctx)
+	if err != nil {
+		return err
+	}
+	log.Println("The graph was created successfully")
+	return nil
+}
+
+func QueryGithub(ctx context.Context, client *ent.Client) error {
+	cars, err := client.Group.
+		Query().
+		Where(group.Name("GitHub")). // (Group(Name=GitHub),)
+		QueryUsers().                // (User(Name=Ariel, Age=30),)
+		QueryCars().                 // (Car(Model=Tesla, RegisteredAt=<Time>), Car(Model=Mazda, RegisteredAt=<Time>),)
+		All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed getting cars: %v", err)
+	}
+	log.Println("cars returned:", cars)
+	// Output: (Car(Model=Tesla, RegisteredAt=<Time>), Car(Model=Mazda, RegisteredAt=<Time>),)
+	return nil
+}
+
+func QueryArielCars(ctx context.Context, client *ent.Client) error {
+	// Get "Ariel" from previous steps.
+	a8m := client.User.
+		Query().
+		Where(
+			user.HasCars(),
+			user.Name("Ariel"),
+		).
+		OnlyX(ctx)
+	cars, err := a8m. // Get the groups, that a8m is connected to:
+				QueryGroups(). // (Group(Name=GitHub), Group(Name=GitLab),)
+				QueryUsers().  // (User(Name=Ariel, Age=30), User(Name=Neta, Age=28),)
+				QueryCars().   //
+				Where(         //
+			car.Not( //	Get Neta and Ariel cars, but filter out
+				car.ModelEQ("Mazda"), //	those who named "Mazda"
+			), //
+		). //
+		All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed getting cars: %v", err)
+	}
+	log.Println("cars returned:", cars)
+	return nil
+}
+
+func QueryGroupWithUsers(ctx context.Context, client *ent.Client) error {
+	groups, err := client.Group.
+		Query().
+		Where(group.HasUsers()).
+		All(ctx)
+	if err != nil {
+		return fmt.Errorf("failed getting groups: %v", err)
+	}
+	log.Println("groups returned:", groups)
+	// Output: (Group(Name=GitHub), Group(Name=GitLab),)
+	return nil
+}