AttributeError：'str'对象没有属性'state_forwards'与django迁移migrations.RunSQL（答案

【问题标题】：AttributeError: 'str' object has no attribute 'state_forwards' with django migrations migrations.RunSQL(AttributeError：'str'对象没有属性'state_forwards'与django迁移migrations.RunSQL（
【发布时间】：2020-09-02 20:49:20
【问题描述】：

我正在尝试将我的 postgres 表的自动生成 id 设置为不同模型的起始值 10000。我使用了this article 并做了以下操作：

python3 manage.py makemigrations core --empty

然后在迁移中我添加了：

    operations = [
        migrations.RunSQL(
                        "ALTER SEQUENCE CORE_ORG_id_seq RESTART WITH 10000",
                        "ALTER SEQUENCE CORE_USER_id_seq RESTART WITH 10000",
                        "ALTER SEQUENCE CORE_PARTLISTING_id_seq RESTART WITH 1000",
                        "ALTER SEQUENCE CORE_BOMITEM_id_seq RESTART WITH 1000",
                        "ALTER SEQUENCE CORE_MANUFACTURER_id_seq RESTART WITH 1000;"
        ),
        migrations.RunSQL(
                        "ALTER SEQUENCE CORE_BOM_id_seq RESTART WITH 1000",
                        "ALTER SEQUENCE CORE_SPECIFICPART_id_seq RESTART WITH 10000",
                        "ALTER SEQUENCE CORE_GENERICPART_id_seq RESTART WITH 10000;"
                        ),
    ]

我将它们放在两个单独的行中，因为我收到了一个错误，即 __init.py__ 顺便说一句只能接受 6 个命令。

当我对此运行迁移时，我得到：

  File "manage.py", line 21, in <module>
    main()
  File "manage.py", line 17, in main
    execute_from_command_line(sys.argv)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
    utility.execute()
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/core/management/__init__.py", line 395, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/core/management/base.py", line 330, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/core/management/base.py", line 371, in execute
    output = self.handle(*args, **options)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/core/management/base.py", line 85, in wrapped
    res = handle_func(*args, **kwargs)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/core/management/commands/migrate.py", line 243, in handle
    post_migrate_state = executor.migrate(
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/db/migrations/executor.py", line 117, in migrate
    state = self._migrate_all_forwards(state, plan, full_plan, fake=fake, fake_initial=fake_initial)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/db/migrations/executor.py", line 147, in _migrate_all_forwards
    state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/db/migrations/executor.py", line 227, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/db/migrations/migration.py", line 114, in apply
    operation.state_forwards(self.app_label, project_state)
  File "/Users/myname/.local/share/virtualenvs/mobiusAPI-NVQT3lgx/lib/python3.8/site-packages/django/db/migrations/operations/special.py", line 101, in state_forwards
    state_operation.state_forwards(app_label, state)
AttributeError: 'str' object has no attribute 'state_forwards'

我还尝试在我的 psql shell 中单独运行这些命令并且它们可以工作，所以我认为这不是模型或表的问题。我想把它放在我的迁移中，所以我确保如果另一个人设置本地数据库会发生这种情况。什么是 state_forwards 为什么会出现这个错误？

感谢您的帮助！

【问题讨论】：

标签： django django-migrations

【解决方案1】：

只有RunSql 参数中的第一个是查询。

签名是：RunSQL(sql, reverse_sql=None, state_operations=None, hints=None, elidable=False)

所以您将第三个查询作为 state_operation 传递，它需要一个操作列表。

每个查询需要有 1 个RunSql，或者根据文档，传递一个 sql 查询数组：

operations = [
  migrations.RunSQL([
    "QUERY1",
    "QUERY2",
    ...
    ])
]

【讨论】：