[aidos]

Alembic. It's made by zzzeek (Mike Bayer), who created SQLA and it's hackable to do custom migrations.

We use it by changing the models in code and then having Alembic automatically create a suitable migration for us. Then we change the migration as required (adding steps for data migrations etc). It's really simple:

    alembic revision --autogenerate -m 'changing something...'

That generates a python file with an upgrade and downgrade function. You can then customise fully as you require.

Then on the db server you can run:

    alembic upgrade head  # or downgrade etc