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

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

更新models字段

出现的问题：

$ python manage.py makemigrationsNoneYou 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: 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.pySelect 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=1, choices=(        (‘1‘, "配置文件"),        (‘2‘, "sls文件"),    ), blank=True, null=True)

再执行

$ python manage.py makemigrationsNoneMigrations 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 makemigrationsNoneMigrations for ‘minions‘:  apps\minions\migrations\0010_filejinja.py    - Create model FileJinjaliangshuo@zt-2013326 MINGW64 /f/11_goms/goms (master)$ python manage.py migrateNoneOperations to perform:  Apply all migrations: admin, auth, contenttypes, minions, salt, sessionsRunning migrations:  Applying minions.0010_filejinja... OK

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