迁移时Django FieldDoesNotExist异常

Question

使用 Django 1.9。 所以我正在尝试迁移我的数据库，但是我遇到了这个错误。 我花了很多时间试图解决这个问题，但没有成功。 如果有必要，我可以上传更多我的代码。 这是错误：

C:\Users\James\Desktop\James\Work\django\homepgcom>python manage.py migrate
Operations to perform:
  Apply all migrations: auth, interface, sessions, admin, contenttypes, userprofile
Running migrations:
  Rendering model states... DONE
  Applying interface.0002_auto_20160107_1635...Traceback (most recent call last):  
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\django\db\models\options.py", line 580, in get_field
return self.fields_map[field_name]
KeyError: None
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "manage.py", line 10, in <module>
execute_from_command_line(sys.argv)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\django\core\management\__init__.py", line 350, in execute_from_command_line
utility.execute()
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\core\management\__init__.py", line 342, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\core\management\base.py", line 348, in run_from_argv
self.execute(*args, **cmd_options)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\core\management\base.py", line 399, in execute
output = self.handle(*args, **options)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\core\management\commands\migrate.py", line 200, in handle
executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\migrations\executor.py", line 92, in migrate
self._migrate_all_forwards(plan, full_plan, fake=fake, fake_initial=fake_initial)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\migrations\executor.py", line 121, in _migrate_all_forwards
state = self.apply_migration(state, migration, fake=fake, fake_initial=fake_initial)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\migrations\executor.py", line 198, in apply_migration
state = migration.apply(state, schema_editor)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\migrations\migration.py", line 123, in apply
operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\migrations\operations\fields.py", line 201, in database_forwards
schema_editor.alter_field(from_model, from_field, to_field)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\backends\base\schema.py", line 482, in alter_field
old_db_params, new_db_params, strict)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\backends\sqlite3\schema.py", line 245, in _alter_field
self._remake_table(model, alter_fields=[(old_field, new_field)])
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\backends\sqlite3\schema.py", line 181, in _remake_table
self.create_model(temp_model)
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\backends\base\schema.py", line 250, in create_model
to_column = field.remote_field.model._meta.get_field(field.remote_field.field_name).column
File "C:\Users\James\AppData\Local\Programs\Python\Python35\lib\site-packages\
django\db\models\options.py", line 582, in get_field
raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, field_name))
django.core.exceptions.FieldDoesNotExist: User has no field named None

提前谢谢了！

Answer 1

发布这篇文章大约五分钟后，我想出了一个解决方案。 我想我会分享它，以防将来有人遇到这个问题。

1. 删除所有应用的所有迁移
2. 为所有应用程序运行python manage.py makemigrations <appname>
3. 然后迁移python manage.py migrate

那么一切应该就好了

感觉自己是个白痴，花了这么多小时试图解决这个问题，哦，好吧！

Answer 2

对于任何刚接触 Django 的人来说，很容易发现迁移在团队环境中存在有线问题。因为丢失的人正在修改模型并进行迁移 有人做错了并导致了问题。如果它在开发环境中，请删除迁移并重做初始步骤是没有问题的。

但是如果它在生产环境中。你不能删除所有的迁移。如果你这样做，你需要确保新数据库有原始数据库的数据。这比修复有问题的迁移需要很多时间。

所以我想解决问题的正确方法是在运行时检查迁移文件手册

python manage.py migrate

如果发生错误，查找导致问题的字段或表，然后修改错误的迁移文件。

如果有

django.db.utils.OperationalError: (1050, “表 'sometable' 已经存在

Django Table 已经存在将解决您的问题。

如果有一个

django.core.exceptions.FieldDoesNotExist：用户没有名为 None 的字段

这意味着您必须删除 migrats.AddField 或 AlterFields。

operations = [
    migrations.AddField(
        model_name='user',
        name='user_current_plan_id',
        field=models.IntegerField(blank=True, null=True),
    ),
]

如果有

重复的列名

您可以通过重复列名修复它

对我来说，一旦发生错误，不是问题而是一系列问题。。冷静下来，修改错误的迁移文件来修复它比删除所有迁移并重新同步db数据更好的方法。