Ruby on Rails Ruby on Rails ActiveRecord & Database Management

Question 1

What is ActiveRecord in Ruby on Rails?

Accepted Answer

The ORM layer that maps Ruby objects to database tables

Answer

A caching library

Answer

A routing module

Answer

A background job framework

Question 2

Which Rails command generates a new database migration file?

Accepted Answer

rails generate migration AddTitleToArticles

Answer

rails db:new

Answer

rails migrate:create

Answer

rails db:schema

Question 3

What does `rails db:migrate` do?

Accepted Answer

Runs all pending migration files to update the database schema

Answer

Rolls back all migrations

Answer

Exports the database to a file

Answer

Seeds the database with test data

Question 4

In ActiveRecord, what does `has_many :comments` in an Article model define?

Accepted Answer

A one-to-many association where an article has multiple comments

Answer

A validation that requires comments

Answer

A method that counts comments

Answer

A database index on the comments table

Question 5

What is the purpose of `belongs_to :article` in a Comment model?

Accepted Answer

To define the inverse side of a has_many relationship, requiring an article_id foreign key

Answer

To create the articles table

Answer

To validate that comments belong to an article class

Answer

To generate a route for comments under articles

Question 6

Which ActiveRecord method retrieves all records from a table?

Accepted Answer

Model.all

Answer

Model.find_all

Answer

Model.select(*)

Answer

Model.fetch