Migrations

Atsume integrates Alembic for performing semi-automatic database migrations. A migration is a database operation that takes us from a previous definition of the models to the current.

Atsume’s migrations are still under heavy development! While it can handle many simple tasks fine, it may not always catch more complicated model modifications. It’s a good idea to always double-check the generated migration files before running them.

Limitations

Atsume’s automatic generation of migrations largely shares the same list of limitations as Alembic. This notably includes:

• Changes to table, column, or constraint name

• Change of a column’s server_default

To create migrations for these changes, they must be created manually, which is covered later.

Extending Alembic to add support for automatically generating these changes is on the roadmap.

Commands

Making Migrations

Migrations can be created with the makemigrations command.

python manage.py makemigrations

This will make new migrations for any changes in any currently loaded apps.

You can also specify to limit to just a single app.

python manage.py makemigrations -c my_component

Upgrading and downgrading migrations

You can apply all generated migrations with the upgrade command.

python manage.py upgrade

You can also specify a specific app or revision number to upgrade to.

python manage.py upgrade my_component

Auto-formatting Migrations

Migrations are automatically formatted if you have the black package installed.

pip install black