mirror of
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93 lines
1.9 KiB
Go
93 lines
1.9 KiB
Go
// Copyright 2019-present Facebook Inc. All rights reserved.
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// This source code is licensed under the Apache 2.0 license found
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// in the LICENSE file in the root directory of this source tree.
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package main
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import (
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"context"
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"fmt"
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"log"
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"entgo.io/ent/examples/m2mrecur/ent/user"
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"entgo.io/ent/examples/m2mrecur/ent"
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_ "github.com/mattn/go-sqlite3"
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)
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func Example_m2mRecur() {
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client, err := ent.Open("sqlite3", "file:ent?mode=memory&cache=shared&_fk=1")
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if err != nil {
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log.Fatalf("failed opening connection to sqlite: %v", err)
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}
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defer client.Close()
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ctx := context.Background()
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// Run the auto migration tool.
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if err := client.Schema.Create(ctx); err != nil {
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log.Fatalf("failed creating schema resources: %v", err)
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}
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if err := Do(ctx, client); err != nil {
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log.Fatal(err)
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}
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// Output:
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// [User(id=2, age=28, name=nati)]
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// []
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// []
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// [User(id=1, age=30, name=a8m)]
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// [28]
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// [a8m]
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}
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func Do(ctx context.Context, client *ent.Client) error {
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// Unlike `Save`, `SaveX` panics if an error occurs.
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a8m := client.User.
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Create().
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SetAge(30).
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SetName("a8m").
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SaveX(ctx)
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nati := client.User.
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Create().
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SetAge(28).
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SetName("nati").
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AddFollowers(a8m).
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SaveX(ctx)
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// Query following/followers:
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flw := a8m.QueryFollowing().AllX(ctx)
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fmt.Println(flw)
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// Output: [User(id=2, age=28, name=nati)]
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flr := a8m.QueryFollowers().AllX(ctx)
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fmt.Println(flr)
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// Output: []
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flw = nati.QueryFollowing().AllX(ctx)
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fmt.Println(flw)
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// Output: []
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flr = nati.QueryFollowers().AllX(ctx)
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fmt.Println(flr)
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// Output: [User(id=1, age=30, name=a8m)]
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// Traverse the graph:
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ages := nati.
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QueryFollowers(). // [a8m]
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QueryFollowing(). // [nati]
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GroupBy(user.FieldAge). // [28]
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IntsX(ctx)
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fmt.Println(ages)
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// Output: [28]
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names := client.User.
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Query().
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Where(user.Not(user.HasFollowers())).
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GroupBy(user.FieldName).
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StringsX(ctx)
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fmt.Println(names)
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// Output: [a8m]
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return nil
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}
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