解决Django-makemigrations-error

问题

使用Django，创建迁移文件的时候，提示如下报错↓：

python manage.py makemigrations
**You are trying to add a non-nullable field ‘phone’ to student 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

解决(models.py)：

• 方法一

phone = models.CharField(max_length=128, verbose_name='电话',null=True,blank=True)

• 方法二

phone = models.CharField(max_length=128, verbose_name='电话',default='blank')

区别：

设置default=’blank’ 时，会在前端phone 一栏，表中默认填充 blank （如下图↓）.