Django 1.9.13 cannot rename a many to many model AttributeError: 'unicode'

Question

我正在重命名多对多模型，删除最后一个 's'

class ModelA(models.Model):

class ModelB(models.Model):
    manytomany = models.ManyToManyField(ModelA, through='ManyToManyModels')

class ManyToManyModels(models.Model):

至

class ModelA(models.Model):

class ModelB(models.Model):
    manytomany = models.ManyToManyField(ModelA, through='ManyToManyModel')

class ManyToManyModel(models.Model):

我可以使用 makemigrations 正确创建迁移，它会询问我是否重命名了模型。但是当我迁移时我得到这个错误：

./manage.py migrate
  File "./manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/lib/python2.7/site-packages/django/core/management/__init__.py", line 353, in execute_from_command_line
    utility.execute()
  File "/lib/python2.7/site-packages/django/core/management/__init__.py", line 345, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/lib/python2.7/site-packages/django/core/management/base.py", line 348, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/lib/python2.7/site-packages/django/core/management/base.py", line 399, in execute
    output = self.handle(*args, **options)
  File "/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 200, in handle
    executor.migrate(targets, plan, fake=fake, fake_initial=fake_initial)
  File "/lib/python2.7/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 "/lib/python2.7/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 "/lib/python2.7/site-packages/django/db/migrations/executor.py", line 198, in apply_migration
    state = migration.apply(state, schema_editor)
  File "/lib/python2.7/site-packages/django/db/migrations/migration.py", line 123, in apply
    operation.database_forwards(self.app_label, schema_editor, old_state, project_state)
  File "/lib/python2.7/site-packages/django/db/migrations/operations/fields.py", line 201, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/lib/python2.7/site-packages/django/db/backends/base/schema.py", line 465, in alter_field
    old_field.remote_field.through._meta.auto_created and
AttributeError: 'unicode' object has no attribute '_meta'

Answer 1

由于 Selcuk 的回答，我解决了这个问题。

因此，我将它分成两个迁移，而不是在同一个迁移中执行所有操作。

第一步.

我用我想要的名称创建了一个新的 M2M。

class ModelA(models.Model):

class ModelB(models.Model):
    manytomany = models.ManyToManyField(ModelA, through='ManyToManyModels')

class ManyToManyModels(models.Model):

class ManyToManyModel(models.Model):

第二步.

我编辑直通字段，将其指向新的 M2M 模型并删除旧的 M2M。

class ModelA(models.Model):

class ModelB(models.Model):
    manytomany = models.ManyToManyField(ModelA, through='ManyToManyModel')

class ManyToManyModel(models.Model):

Django 1.9.13 cannot rename a many to many model AttributeError: 'unicode'

Django 1.9.13 cannot rename a many to many model AttributeError: 'unicode'

django

django-models

django-migrations