Deleting a table from MySQL database in Django manually

Question

During my experimentation with my blog app (blogapp) in Django, I created two models (Category and Language), connected them to another model (Post) using following connections:

category = models.ManyToManyField(Category)
language = models.ForeignKey(Language)

Then it gave an error like THIS due to the lack of default value. Tried to roll that back by using an amalgam of THIS and THIS. Then I tried to add a default value using THIS. I've got an error "django.db.utils.OperationalError 1050, Table XXX already exists", then I tried THIS. Tried to revert back migrations by deleting the created migrations from the migrations folder manually. At some point I got django (1054, "Unknown column in 'field list") error.

Finally I decided to revert back to my original starting place. When I connect to my MySQL database using python manage.py dbshell, I realized that my MySQL server still have two tables that should have been deleted, blogapp_category and blogapp_language. Server is working properly but I keep getting "Table XXX already exists" error when I try to add those models.

Dropping tables from MySQL seems to be the only option at the moment. When I run

mysql> SHOW COLUMNS FROM blogapp_post;

I did not see any reference to language or category, i.e. no columns named language_id or category_id. I have two questions at the moment:

1. Is it safe to delete tables manually using:

   DROP TABLE blogapp_language; DROP TABLE blogapp_category;

Will there be any negative effects?

2. Is there a way to freeze database like git so that when I revert to the old database, such tables added to the database by django migrations automatically dropped??

Answer 1

1. Delete respective entry from table django_migrations.
2. Delete migration folder from your app.
3. Delete table created by the app.

Now do makemigrations and migrate.

You can revert back using git but there will be errors and data correction requirements.