Squash multiple migrations into one

Question

I did multiple minor migrations.

1. Add column A
2. Remove column A
3. Add column A

Is it possible to squash these migrations into one?

Answer 1

There's no automatic way to do it, but it's pretty straightforward to do it manually. For illustration, you have the following migrations A through E and all migrations are applied to the database (current is E). You want to squash C through E.

A > B > C > D > E

1. Copy the contents of the upgrade and downgrade functions from C and D into E. Maintain the order of operations, and remove redundant operations (in your example you'd actually just end up with the contents of E).
2. Change the down_revision of E to point to B instead of D.
3. Delete C and D, which are no longer connected to the graph.