Rails Migration

Definitions

1. A Ruby class in Rails that describes a reversible change to the database schema — creating tables, adding columns, building indexes — using a DSL rather than raw DDL. Migrations are timestamped, version-tracked in the schema_migrations table, and applied in order via rake db:migrate, making schema changes reproducible across environments.

   In plain English: A script that describes a change to a database's structure in a way that can be applied, shared with teammates, and undone if needed.

   Example: "I generated a migration to add a deleted_at column for soft deletes — run rake db:migrate and you're good."

Related Terms

• ORM
• Migration
• CRUD
• KV Store
• Left Join
• Query Builder
• Rails Router
• RDBMS