Django - 一个模型不能有多个 AutoField

Question

This problem randomly started appearing for me. I know that Django generates its own ids but a lot my code has been using custom AutoFields which HAS been working. I added a new class today and tried to makemigrations but this error keeps showing up.

I DID remove all instances of AutoFields and retried migrating but the problem still persists which leads me to believe it's something else... I don't believe my Django version has changed at all...

Error:

    Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "C:\Python34\lib\site-packages\django\core\management\__init__.py", line
338, in execute_from_command_line
    utility.execute()
  File "C:\Python34\lib\site-packages\django\core\management\__init__.py", line
330, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "C:\Python34\lib\site-packages\django\core\management\base.py", line 390,
 in run_from_argv
    self.execute(*args, **cmd_options)
  File "C:\Python34\lib\site-packages\django\core\management\base.py", line 441,
 in execute
    output = self.handle(*args, **options)
  File "C:\Python34\lib\site-packages\django\core\management\commands\makemigrat
ions.py", line 98, in handle
    loader.project_state(),
  File "C:\Python34\lib\site-packages\django\db\migrations\loader.py", line 326,
 in project_state
    return self.graph.make_state(nodes=nodes, at_end=at_end, real_apps=list(self
.unmigrated_apps))
  File "C:\Python34\lib\site-packages\django\db\migrations\graph.py", line 231,
in make_state
    project_state = self.nodes[node].mutate_state(project_state, preserve=False)

  File "C:\Python34\lib\site-packages\django\db\migrations\migration.py", line 8
3, in mutate_state
    operation.state_forwards(self.app_label, new_state)
  File "C:\Python34\lib\site-packages\django\db\migrations\operations\fields.py"
, line 51, in state_forwards
    state.reload_model(app_label, self.model_name_lower)
  File "C:\Python34\lib\site-packages\django\db\migrations\state.py", line 152,
in reload_model
    self.apps.render_multiple(states_to_be_rendered)
  File "C:\Python34\lib\site-packages\django\db\migrations\state.py", line 262,
in render_multiple
    model.render(self)
  File "C:\Python34\lib\site-packages\django\db\migrations\state.py", line 546,
in render
    body,
  File "C:\Python34\lib\site-packages\django\db\models\base.py", line 189, in __
new__
    new_class.add_to_class(obj_name, obj)
  File "C:\Python34\lib\site-packages\django\db\models\base.py", line 324, in ad
d_to_class
    value.contribute_to_class(cls, name)
  File "C:\Python34\lib\site-packages\django\db\models\fields\__init__.py", line
 989, in contribute_to_class
    "A model can't have more than one AutoField."
AssertionError: A model can't have more than one AutoField.

Here's an example of one of my fields:

assetid = models.AutoField(primary_key=True)

A lot of my code already depends on the name itself so changing it is going to be a big issue. Furthermore, this was working perfectly before! I just can't seem to migrate it now. I should mention im using a sqlite3 db.

Answer 1

This is Because Django By default uses AutoField for the id.....so, if you want other fields to be AutoField, then make sure you confirm primary_key=True . Doing so deletes the id field from the Database.

I have used Mysql as my database. Be sure this problem might not solve in other databases.

Answer 2

删除了迁移文件和最近的历史记录并修复了它。

Answer 3

I was having the same problem,

I commented out all the references to that model in all my app files, then run makemigrations and migrate, butit keeps telling that "A model can't have more than one AutoField." even if i am trying to deleting that file.

I had to reset my database.

Answer 4

在我的情况下，我删除了 id Autofield ，它对我来说很好，因为 Django 默认使用 Autofield

Answer 5

更好的方法是取消应用迁移（意味着运行以前的迁移）。这样，有时不会从数据库中删除的字段会自动从数据库中删除。然后，在更改之后，您可以轻松地再次进行 makemigrations 然后迁移，一切都会好起来的.