我在Django换了很多场地的时候把数据库弄坏了吗？

Question

所以我有一个ForeignKey字段，我需要将它转换成many many字段。当我运行迁移时，它给出了以下错误：

ValueError: Cannot alter field core_app.IndieTrack.contributors into core_app.IndieTrack.contributors - they are not compatible types (you cannot alter to or from M2M fields, or add or remove through= on M2M fields)

所以我说，“好吧，”然后我又把它恢复到ForeignKey上，我想我会想出另一个解决方案。但是当我再次迁移（回到原始状态）时，它给了我同样的错误。在

现在我根本无法迁移任何更改。不管我做什么，我都会犯同样的错误。在

这是整个追踪过程：

python3.4 manage.py makemigrations core_app              Migrations for 'core_app':
  0034_auto_20150521_0740.py:
    - Create model UserTrack
    - Remove field contributors from indietrack
    - Delete model IndieTrack
    - Alter field tracks on album
python3.4 manage.py migrate
Operations to perform:
  Apply all migrations: sessions, home, auth, admin, ipn, beat_store, blog, core    _app, contenttypes
Running migrations:
  Applying core_app.0024_auto_20150521_0634...Traceback (most recent call last):

Running migrations:
  Applying core_app.0024_auto_20150521_0634...Traceback (most recent call last):
  File "manage.py", line 10, in <module>
    execute_from_command_line(sys.argv)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/__init__.py", line 385, in execute_from_command_line
    utility.execute()
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/__init__.py", line 377, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/base.py", line 288, in run_from_argv
    self.execute(*args, **options.__dict__)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/base.py", line 533, in handle
    return self.handle_noargs(**options)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/commands/syncdb.py", line 27, in handle_noargs
    call_command("migrate", **options)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/__init__.py", line 115, in call_command
    return klass.execute(*args, **defaults)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/base.py", line 338, in execute
    output = self.handle(*args, **options)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/core/management/commands/migrate.py", line 161, in handle
    executor.migrate(targets, plan, fake=options.get("fake", False))
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/db/migrations/executor.py", line 68, in migrate
    self.apply_migration(migration, fake=fake)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/db/migrations/executor.py", line 102, in apply_migration
    migration.apply(project_state, schema_editor)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/db/migrations/migration.py", line 108, in apply
    operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/db/migrations/operations/fields.py", line 139, in database_forwards
    schema_editor.alter_field(from_model, from_field, to_field)
  File "/home/thephltr/webapps/who_pro/lib/python3.4/Django-1.7.7-py3.4.egg/django/db/backends/schema.py", line 454, in alter_field
    new_field,
ValueError: Cannot alter field core_app.IndieTrack.contributors into core_app.IndieTrack.contributors - they are not compatible types (you cannot alter to or from M2M fields, or add or remove through= on M2M fields)

这是我的模型：

^{pr2}$

我需要做些改变。任何有见识的人都将不胜感激。在

我用的是PostgreSQL

Answer 1

如果您只更改了该字段，那么我建议您返回migrations文件夹并删除在您尝试将其更改为manytomy字段后创建的迁移文件夹。因为您已经创建了上述迁移，并且Django按顺序运行它们，所以它将继续尝试运行它，因为在此之后进行的迁移依赖于它，并且错误将不断出现。这是我为了自己的理智而这样做的。在

如果您更改了其他字段，也许可以输入该迁移文件并删除与该字段相关的位。在