python manage.py makemigrat Please select a fix: 1) Provide a one-off default now (will be set on all existing rows with a null value for this column) 2) Quit, and let me add a default in models.py

更新models字段

出现的问题：

$ python manage.py makemigrations
None
You are trying to add a non-nullable field 'file_type' to filejinja without a default; we can't do that (the database needs something to populate existing rows).
Please select a fix:
 ) Provide a one-off default now (will be set on all existing rows with a null value for this column)
 ) Quit, and let me add a default in models.py
Select an option:

原因：

之前数据表里面已经存在，如果添加，file_type需要默认值

解决：

方法1：

在model字段后面添加，

 blank=True, null=True

    file_type = models.CharField(verbose_name="文件type", max_length=, choices=(
        ('', "配置文件"),
        ('', "sls文件"),
    ), blank=True, null=True)

再执行

$ python manage.py makemigrations
None
Migrations for 'minions':
  apps\minions\migrations\0011_filejinja_file_type.py
    - Add field file_type to filejinja

方法2：

数据库中找到django_migrations，该表对应，每次makemigrations的每次记录

删除，生成的migrations

在删除你要更新的表。

重新生成新的表

$ python manage.py makemigrations
None
Migrations for 'minions':
  apps\minions\migrations\0010_filejinja.py
    - Create model FileJinja

liangshuo@zt- MINGW64 /f/11_goms/goms (master)
$ python manage.py migrate
None
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, minions, salt, sessions
Running migrations:
  Applying minions.0010_filejinja... OK