Think I was using the wrong terminology. What I meant is that your ORM code in the app needs to reflect your database pretty much exactly, otherwise you can get

Think I was using the wrong terminology. What I meant is that your ORM code in the app needs to reflect your database pretty much exactly, otherwise you can get unwanted migrations. Which is in most cases desirable, but for example if you want to use database features that SQLAlchemy/Alembic don't (yet) support it can get a bit messy and/or require some manual plumbing to keep getting the migrations you want.