I have recently messed up my Alembic migrations while modifying my SQLAlchemy models. To start with, I didn’t update the auto-generated migration files to name the indexes/foreign keys a name, so Alembic used its own naming scheme. This is not an actual problem until you have to modify columns that have such constraints. I have since fixed this problem, but first I had to find which column references what (I had no indexes other than primary key back then, so I could go with foreign keys only). Here is a query I put together, mostly using this article.