Running and rolling back migrations in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What command runs all pending migrations in Rails?

Use rails db:migrate to run all migrations that have not yet been applied to the database.

beginner

How do you rollback the last migration in Rails?

Use rails db:rollback to undo the last migration that was run.

beginner

What does rails db:migrate:status show?

It shows a list of all migrations and whether each one has been applied (up) or not (down).

intermediate

How can you rollback multiple migrations at once?

Use rails db:rollback STEP=n where n is the number of migrations to undo.

intermediate

What is the difference between rails db:rollback and rails db:migrate:down VERSION=xxxx?

rails db:rollback undoes the last migration by default, while rails db:migrate:down VERSION=xxxx rolls back a specific migration by its version number.

Which command runs all pending migrations in Rails?

A rails db:migrate

B rails db:rollback

C rails db:migrate:status

D rails db:seed

rails db:migrate runs all migrations that have not yet been applied.

How do you undo the last migration in Rails?

A rails db:migrate

B rails db:reset

C rails db:rollback

D rails db:seed

rails db:rollback undoes the last migration.

What does rails db:migrate:status display?

A Current Rails version

B Database schema version

C List of seeds applied

D List of migrations and their applied status

This command shows which migrations are up or down.

How to rollback the last 3 migrations?

A rails db:rollback STEP=3

B rails db:migrate STEP=3

C rails db:rollback 3

D rails db:migrate:down STEP=3

Use rails db:rollback STEP=3 to undo the last three migrations.

Which command rolls back a specific migration by version?

A rails db:rollback STEP=1

B rails db:migrate:down VERSION=xxxx

C rails db:migrate:up VERSION=xxxx

D rails db:reset

rails db:migrate:down VERSION=xxxx rolls back a specific migration.

Explain how to run migrations and then undo the last migration in Rails.

Think about commands to apply changes and then reverse the last change.

Describe how to check migration status and rollback multiple migrations in Rails.

Consider commands that show migration states and undo several steps.