第二次修改models.py以后再次
python manage.py makemigrations
提示如下
You are trying to add a non-nullable field 'address' to xc_users 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) 2) Qu
于是删除数据库表，继续报相同的错误
makemigration需要指定名称，然后migrate才能识别两次<span style="font-family: Arial, Helvetica, sans-serif;">makemigrations的不同</span>
python manage.py makemigrations --name sqlname
然后再执行：
python manage.py migrate
成功解决问题