Django You are trying to add a n

因为之前数据库中已经有数据了，现在加了一个字段，这个字段没有默认值，它不知道该怎么填什么东西，所以它会报错，并且有两种解决方法： 1.在当前cmd报错状态下输入1，然后输入字符串，如果是时间，则输入timezone.now 2.在models下添加default即可

name = models.CharField(max_length=50)

执行：python manage.py makemirations出现以下错误：

You are trying to add a non-nullable field 'name' to contact 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.py

Select an option: 

解决方法：

先给'name'任意初始值：name = models.CharField(max_length=50, default='abc')

然后执行：python manage.py makemirations

再执行：python manage.py migrate

再将default删去，即执行：name = models.CharField(max_length=50)

执行：python manage.py makemirations

再执行：python manage.py migrate

原文链接：https://blog.csdn.net/check2255/java/article/details/70338443