Are database migrations necessary?

Should you use database migrations?

Migrations are helpful because they allow database schemas to evolve as requirements change. They help developers plan, validate, and safely apply schema changes to their environments.

Why data migration is needed?

Data migration allows us to get all of our data into a single storage system like a cloud data warehouse, data lake, or lakehouse. If analysts and other employees can access all of the data they need from a single system, they can start using it right away to make better decisions, resulting in faster time to insight.

When should you run DB migrations?

Run the database migrations first, before you deploy the new code. This means the before code must work with both database schemas, but the after code can assume that the tables have already been added.

Should I delete old migrations?

You don't need to keep around your old migration files in a Rails app, because your database schema should be captured either in schema. rb or an equivalent SQL file that can be used to regenerate your schema. Migrations are not the authoritative source for your database schema. That role falls to either db/schema.