南方计划迁移显然没有奏效

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，我运行了如下所示的架构迁移：

    $ 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

我以为我改变了它？我做错了什么？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达到当前状态（更改之前），并且它们会定期迁移。

编辑（基于 cmets）：

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 是伪造的，这很好，因为您可能不希望南更改更改前状态的 db 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

查看已应用迁移的列表

./manage.py migrate locationmanager --list