解决Django migrate No changes detected 不能创建表的问题

django.db.utils.OperationalError: (1091, "Can't DROP 'email'; check that column/key exists")

python3 manage.py makemigrations
python3 manage.py migrate

$ rm -rf migrations/ __pycache__/

$ python3 manage.py makemigrations
No changes detected
$~/code/django/blogproject$ python3 manage.py makemigrations comments
Migrations for 'comments':
 comments/migrations/0001_initial.py
 - Create model Comment
$~/code/django/blogproject$ python3 manage.py migrate
Operations to perform:
 Apply all migrations: admin, auth, blog, comments, contenttypes, sessions, users
Running migrations:
 No migrations to apply.

delete from django_migrations where app='yourappname';

$ python3 manage.py makemigrations comments
No changes detected in app 'comments'
$~/code/django/blogproject$ python3 manage.py migrate comments
Operations to perform:
 Apply all migrations: comments
Running migrations:
 Applying comments.0001_initial... OK

python3 manage.py makemigrations python3 manage.py migrate