mirror of
https://github.com/ent/ent.git
synced 2026-05-22 09:31:45 +03:00
47 lines
1.3 KiB
Go
47 lines
1.3 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/version/ent"
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_ "entgo.io/ent/examples/version/ent/runtime"
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"entgo.io/ent/examples/version/ent/user"
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_ "github.com/mattn/go-sqlite3"
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)
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func Example_OptimisticLock() {
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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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usr := client.User.Create().SetStatus(user.StatusOnline).SaveX(ctx)
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fmt.Println(usr.ID, usr.Status)
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usrCopy := client.User.Query().OnlyX(ctx)
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usrCopy = usrCopy.Update().SetStatus(user.StatusOffline).SaveX(ctx)
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fmt.Println(usrCopy.ID, usrCopy.Status)
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// The operation fails because the user was updated by another process (usrCopy).
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_, err = usr.Update().SetStatus(user.StatusOffline).Save(ctx)
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fmt.Println(err)
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// Output:
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// 1 online
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// 1 offline
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// user 1 was changed by another process
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}
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