Callbacks overview in Ruby on Rails - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a callback in Rails?

A callback in Rails is a method that gets called at certain points in an object's life cycle, like before saving or after creating a record.

beginner

Name two common types of callbacks in Rails.

Two common callbacks are before_save and after_create. They run before saving and after creating a record, respectively.

intermediate

How do callbacks help in managing data integrity?

Callbacks let you run code automatically to check or change data before saving, ensuring the data stays correct and consistent.

intermediate

What is the difference between before_save and after_save callbacks?

before_save runs before the record is saved to the database, allowing changes or checks. after_save runs after the record is saved, useful for actions that depend on the saved data.

intermediate

Can callbacks stop a save operation in Rails? How?

Yes, callbacks like before_save can stop saving by throwing an exception or by adding errors to the object, which prevents the save.

Which callback runs right before a record is saved in Rails?

A before_create

B before_save

C after_save

D after_create

before_save runs just before saving a record, allowing changes or checks.

What happens if a before_save callback returns false?

A The save operation is canceled

B The save operation continues

C An error is raised immediately

D The callback is ignored

Returning false in a before_save callback used to stop the save operation in older Rails versions, but in modern Rails versions, you should throw an exception or add errors to stop saving.

Which callback would you use to run code after a new record is created?

A after_create

B before_create

C before_save

D after_save

after_create runs after a new record is successfully created.

Callbacks in Rails are mainly used to:

A Handle user authentication

B Manually trigger database queries

C Replace model validations

D Automatically run code at certain object lifecycle events

Callbacks automatically run code at specific points like before saving or after creating.

Which callback is best to modify data before saving it to the database?

A after_create

B after_save

C before_save

D after_destroy

before_save allows you to change data before it is saved.

Explain what Rails callbacks are and give two examples of when they run.

Think about moments in a record's life like saving or creating.

Describe how callbacks can be used to prevent saving invalid data in Rails.

Consider how callbacks can stop an action if conditions are not met.