juniorRuby on Rails
What are Rails migrations?
Updated May 24, 2026
Short answer
Migrations are version-controlled database schema changes.
Deep explanation
They allow evolving database structure safely over time using Ruby scripts tracked in version control.
Real-world example
Adding new fields like 'phone number' to users table in production apps.
Common mistakes
- Editing old migrations instead of creating new ones.
Follow-up questions
- How to rollback migrations?
- What is schema.rb?