class Meta index_together属性用不了

Question

Traceback (most recent call last):
  File "C:\Users\***\PycharmProjects\myshop\myshop\manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "E:\code\python 3.12\Lib\site-packages\django\core\management\__init__.py", line 442, in execute_from_command_line
    utility.execute()
  File "E:\code\python 3.12\Lib\site-packages\django\core\management\__init__.py", line 436, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "E:\code\python 3.12\Lib\site-packages\django\core\management\base.py", line 413, in run_from_argv
    self.execute(*args, **cmd_options)
  File "E:\code\python 3.12\Lib\site-packages\django\core\management\base.py", line 459, in execute
    output = self.handle(*args, **options)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\core\management\base.py", line 107, in wrapper
    res = handle_func(*args, **kwargs)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\core\management\commands\migrate.py", line 357, in handle
    post_migrate_state = executor.migrate(
                         ^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\executor.py", line 135, in migrate
    state = self._migrate_all_forwards(
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\executor.py", line 167, in _migrate_all_forwards
    state = self.apply_migration(
            ^^^^^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\executor.py", line 255, in apply_migration
    state = migration.apply(state, schema_editor)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\migration.py", line 118, in apply
    operation.state_forwards(self.app_label, project_state)
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\operations\models.py", line 662, in state_forwards
    state.alter_model_options(
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\state.py", line 188, in alter_model_options
    self.reload_model(app_label, model_name, delay=True)
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\state.py", line 399, in reload_model
    self._reload(related_models)
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\state.py", line 434, in _reload
    self.apps.render_multiple(states_to_be_rendered)
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\state.py", line 664, in render_multiple
    model.render(self)
  File "E:\code\python 3.12\Lib\site-packages\django\db\migrations\state.py", line 957, in render
    return type(self.name, bases, body)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "E:\code\python 3.12\Lib\site-packages\django\db\models\base.py", line 143, in __new__
    new_class.add_to_class("_meta", Options(meta, app_label))
  File "E:\code\python 3.12\Lib\site-packages\django\db\models\base.py", line 371, in add_to_class
    value.contribute_to_class(cls, name)
  File "E:\code\python 3.12\Lib\site-packages\django\db\models\options.py", line 220, in contribute_to_class
    raise TypeError(
TypeError: 'class Meta' got invalid attribute(s): index_together

怎么办啊，这个问题如何解决？

Answer 1

以下回复参考：皆我百晓生、券券喵儿等免费微信小程序作答:

看起来你在使用Django的模型（Model）时遇到了一个问题，错误信息表明在你的模型的 Meta 类中，有一个无效的属性 'index_together'，导致了错误。这个问题是因为在Django的版本中，"index_together"已经被弃用并且在新版本中被移除了，所以你无法在Django的新版本中继续使用它。你需要使用索引的替代方案来创建复合索引。Django不再支持直接通过 "index_together" 选项创建复合索引，而是通过设置数据库的字段定义和配置索引。在大多数情况下，你可能不再需要这个选项了。你可以在创建数据库模型时使用 Django 的字段参数和索引方法来实现复合索引。如果你确实需要创建复合索引，你需要直接在数据库层面上操作或使用第三方库来辅助操作。在数据库层面上创建复合索引通常需要写一些数据库特定的SQL语句来完成。例如，在MySQL数据库中，你可以使用如下语句来创建复合索引：

from django.db import models

class MyModel(models.Model):
    field1 = models.CharField(max_length=255)  # Example field
    field2 = models.CharField(max_length=255)  # Another example field
    class Meta:
        db_table = 'my_table'  # Use custom table name in migrations for index
        managed = False  # If not managed, no migrations will be applied, and you need to handle db schema yourself.
        indexes = [models.Index(fields=['field1', 'field2'], name='my_custom_index')]  # Define composite index in the Meta class instead of using index_together.
```在这个例子中，我们首先定义了数据库表的名字和关闭迁移（由于使用了自定义SQL）。然后在 Meta 类中使用 `indexes` 属性定义了一个复合索引 `my_custom_index` 来代替原先的 `index_together` 属性。然后在数据库中创建该索引时直接使用SQL语句或者数据库管理工具进行创建。如果你需要动态创建复合索引或者是在不同数据库上实现不同的复合索引逻辑，可能需要使用第三方库来帮助你管理数据库索引，比如 Django-Index或者Django-ORM扩展库等。这样可以在一定程度上减少编写SQL语句的复杂性。如果你需要更详细的解决方案或指导，可以提供更多关于你的模型和具体的使用场景的信息。这样我可以更精确地为你提供解决方案和代码示例。