Question

Are data definition transactions the same as regular transactions?

I want to write a migration that

1. changes table A
2. does some custom data migrations
3. changes table B

Ideally this would all be inside the same transaction. Can I just stick it in an ActiveRecord migration and call it a day?

Answer 1

Yes, each migration is executed within a transaction. From the Migrations Guide:

On databases that support transactions with statements that change the schema (such as PostgreSQL or SQLite3), migrations are wrapped in a transaction.

So stick it in a migration and call it a day.