Question

好的，所以我有一个名为locationmanager的应用程序，其模型如下所示：

class Location(models.Model):
    region = models.ForeignKey(Region)

我想把它改成这个

class Location(models.Model):
    region = models.ForeignKey(Region, blank=True, null=True)

更改后，我运行了一个类似于以下内容的模式迁移：

    $ python manage.py schemamigration locationmanager --auto
     ? The field 'Location.region' does not have a default specified, yet is NOT NULL.
     ? Since you are making this field nullable, you MUST specify a default
     ? value to use for existing rows. Would you like to:
     ?  1. Quit now.
     ?  2. Specify a one-off value to use for existing columns now
     ?  3. Disable the backwards migration by raising an exception; you can edit the migration to fix it later
     ? Please select a choice: 2
     ? Please enter Python code for your one-off default value.
     ? The datetime module is available, so you can do e.g. datetime.date.today()
     >>> 0
     ~ Changed field region on locationmanager.Location
     ? The field 'Location.manager' does not have a default specified, yet is NOT NULL.
     ? Since you are making this field nullable, you MUST specify a default
     ? value to use for existing rows. Would you like to:
     ?  1. Quit now.
     ?  2. Specify a one-off value to use for existing columns now
     ?  3. Disable the backwards migration by raising an exception; you can edit the migration to fix it later
     ? Please select a choice: 0
     ! Invalid choice.
     ? Please select a choice: 2
     ? Please enter Python code for your one-off default value.
     ? The datetime module is available, so you can do e.g. datetime.date.today()
     >>> 0
     ~ Changed field manager on locationmanager.Location
    Created 0003_auto__chg_field_location_region__chg_field_location_manager.py. You can now apply this migration with: ./manage.py migrate locationmanager

$ sudo python manage.py migrate locationmanager --fake
Running migrations for locationmanager:
 - Migrating forwards to 0003_auto__chg_field_location_region__chg_field_location_manager.
 > locationmanager:0002_initial
   (faked)
 > locationmanager:0003_auto__chg_field_location_region__chg_field_location_manager
   (faked)

运行测试后，表单向我吐出错误：

   IntegrityError at /dash/location/add
    locationmanager_location.region_id may not be NULL

我以为我改变了吗？我能做错什么？我目前可以做些什么来解决这个问题？

Answer 1

您指定--fake迁移。伪造您的初始迁移以进入当前状态（在更改之前）并定期迁移。

编辑（根据评论）：

为了修复迁移，您必须使用

回滚到迁移0002

./manage.py migrate locationmanager 0002

迁移0002是假的，没关系，因为您可能不希望南方在更改之前更改状态的数据库方案。

现在您可以使用

定期迁移到迁移0003

./manage.py migrate locationmanager

请注意，您始终可以使用

查看已应用的迁移列表

./manage.py migrate locationmanager --list

南计划迁移显然不起作用

1 个答案:

编辑（根据评论）：