Fixed Django migrate No changes detected not being able to create tables

The cause of

After modifying the table structure, python3 manage. py migrate error:

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

So I go into the database and Delete the corresponding table, and I want to regenerate this table.

After deleting the table:

python3 manage.py makemigrations
python3 manage.py migrate

Still cannot generate table, hint :No changes detected

The process

First, the files and cache files corresponding to the database under the corresponding directory of app were deleted:

$ rm -rf migrations/ __pycache__/

Re-execute:

$ 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.

Enter the database and still no tables are generated.

Then I found an django_migrations table, which recorded the record of creating the table, and deleted the corresponding data table:

delete from django_migrations where app='yourappname';

Re-execute the generate database command:

$ 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

The data table was generated successfully.

conclusion

In the implementation

python3 manage.py makemigrations python3 manage.py migrate

When you do this, not only will you create the model script for 0001_initial.py, but you will also create a model for creating a database record. If you want to rebuild the database, you need to delete both places.