Initial commit

fbshipit-source-id: c79a38536e3c128dce1b2948615b72ec9779ed22

dialect/sql/schema/sqlite.go

@@ -0,0 +1,74 @@
+package schema
+
+import (
+	"context"
+	"fmt"
+
+	"fbc/ent/dialect"
+	"fbc/ent/dialect/sql"
+)
+
+// SQLite is an SQLite migration driver.
+type SQLite struct {
+	dialect.Driver
+}
+
+// Create creates all tables resources in the database.
+func (d *SQLite) Create(ctx context.Context, tables ...*Table) error {
+	tx, err := d.Tx(ctx)
+	if err != nil {
+		return err
+	}
+	on, err := d.fkEnabled(ctx, tx)
+	if err != nil {
+		return fmt.Errorf("sql/sqlite: check foreign_keys pragma: %v", err)
+	}
+	if !on {
+		// foreign_keys pragma is off, either enable it by execute "PRAGMA foreign_keys=ON"
+		// or add the following parameter in the connection string "_fk=1".
+		return fmt.Errorf("sql/sqlite: foreign_keys pragma is off: missing %q is the connection string", "_fk=1")
+	}
+	for _, t := range tables {
+		exist, err := d.tableExist(ctx, tx, t.Name)
+		if err != nil {
+			return rollback(tx, err)
+		}
+		if exist {
+			continue
+		}
+		query, args := t.SQLite().Query()
+		if err := tx.Exec(ctx, query, args, new(sql.Result)); err != nil {
+			err = fmt.Errorf("sql/sqlite: create table %q: %v", t.Name, err)
+			return rollback(tx, err)
+		}
+	}
+	return tx.Commit()
+}
+
+func (d *SQLite) tableExist(ctx context.Context, tx dialect.Tx, name string) (bool, error) {
+	query, args := sql.Select().Count().
+		From(sql.Table("sqlite_master")).
+		Where(sql.EQ("type", "table").And().EQ("name", name)).
+		Query()
+	return d.exist(ctx, tx, query, args...)
+}
+
+func (d *SQLite) fkEnabled(ctx context.Context, tx dialect.Tx) (bool, error) {
+	return d.exist(ctx, tx, "PRAGMA foreign_keys")
+}
+
+func (d *SQLite) exist(ctx context.Context, tx dialect.Tx, query string, args ...interface{}) (bool, error) {
+	rows := &sql.Rows{}
+	if err := tx.Query(ctx, query, args, rows); err != nil {
+		return false, fmt.Errorf("dialect/sqlite: reading schema information %v", err)
+	}
+	defer rows.Close()
+	if !rows.Next() {
+		return false, fmt.Errorf("dialect/sqlite: no rows returned")
+	}
+	var n int
+	if err := rows.Scan(&n); err != nil {
+		return false, fmt.Errorf("dialect/sqlite: scanning count")
+	}
+	return n > 0, nil
+}