Rails:Migrations

Official Documentation

• https://guides.rubyonrails.org/active_record_migrations.html

Database Types

For list of (postgres) column types, see:

• https://stackoverflow.com/q/17918117/1093087
• https://github.com/rails/rails/blob/master/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb (See NATIVE_DATABASE_TYPES)

Schema Migrations

Generate a Migration

Generic

# rails g migration <name>
rails g migration CreateCruds

Run the Migration

# Run new migrations
rails db:migrate

# Don't forget to test rollbacks on new migrations
rails db:rollback STEP=1

Data Migrations

What if you need to do a data migration or data fix on existing data?

• https://thoughtbot.com/blog/data-migrations-in-rails
• https://github.com/dimroc/datafix