Why associations connect models in Ruby on Rails - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a one-to-many association in Rails.

Ruby on Rails

class Author < ApplicationRecord
  has_many :[1]
end

Drag options to blanks, or click blank then click option'

Abooks

Bbook

Cauthors

Dpublishers

Attempts:

3 left

💡 Hint

Common Mistakes

Using singular form like 'book' instead of plural 'books'.

Using unrelated model names like 'publishers'.

In Rails, has_many expects the plural form of the associated model name, so books is correct.

2fill in blank

medium

Complete the code to declare a belongs_to association in Rails.

Ruby on Rails

class Book < ApplicationRecord
  belongs_to :[1]
end

Drag options to blanks, or click blank then click option'

Abooks

Bpublishers

Cauthor

Dauthors

Attempts:

3 left

💡 Hint

Common Mistakes

Using plural form like 'authors' instead of singular 'author'.

Using unrelated model names like 'publishers'.

The belongs_to association uses the singular form of the related model, so author is correct.

3fill in blank

hard

Fix the error in the association declaration to connect models correctly.

Ruby on Rails

class Publisher < ApplicationRecord
  has_one :[1]
end

Drag options to blanks, or click blank then click option'

Apublishers

Bbooks

Cauthors

Dbook

Attempts:

3 left

💡 Hint

Common Mistakes

Using plural form like 'books' with has_one.

Using unrelated model names.

The has_one association expects the singular form of the related model, so book is correct.

4fill in blank

hard

Fill both blanks to create a has_many through association connecting models.

Ruby on Rails

class Doctor < ApplicationRecord
  has_many :appointments
  has_many :[1], through: :[2]
end

Drag options to blanks, or click blank then click option'

Apatients

Bappointments

Cdoctors

Dhospitals

Attempts:

3 left

💡 Hint

Common Mistakes

Using unrelated models like 'hospitals'.

Mixing up the order of the association names.

Doctors have many patients through appointments, so patients and appointments are correct.

5fill in blank

hard

Fill all three blanks to define a has_many association with dependent destroy option.

Ruby on Rails

class Library < ApplicationRecord
  has_many :[1], dependent: :[2]

  before_destroy :check_[3]
end

Drag options to blanks, or click blank then click option'

Abooks

Bdestroy

Ddelete

Attempts:

3 left

💡 Hint

Common Mistakes

Using singular form for association name.

Using wrong dependent option like 'delete' instead of 'destroy'.

Mismatch between association name and callback method.

The library has many books, and when the library is destroyed, its books are also destroyed. The callback checks for books before destroying.