belongs_to relationship in Ruby on Rails - Mini Project: Build & Apply

Understanding belongs_to Relationship in Rails

📖 Scenario: You are building a simple blog application where each Comment belongs to a Post. This means every comment is linked to exactly one post.

🎯 Goal: Create a Comment model that correctly uses the belongs_to relationship to associate each comment with a post.

📋 What You'll Learn

Create a Post model with a title attribute

Create a Comment model with a content attribute

Add a belongs_to :post association in the Comment model

Add a has_many :comments association in the Post model

💡 Why This Matters

🌍 Real World

This pattern is common in blog platforms, forums, and social media apps where items like comments, reviews, or replies belong to a main post or item.

💼 Career

Understanding belongs_to and has_many associations is essential for Rails developers to model database relationships correctly and build functional web applications.

1

Create the Post model with a title

Create a Rails model called Post with a string attribute title.

Ruby on Rails

# Create Post model with title attribute
# Your code here

Need a hint?

Use rails generate model Post title:string to create the model with the title attribute.

2

Create the Comment model with content and post reference

Create a Rails model called Comment with a string attribute content and a reference to post (foreign key).

Ruby on Rails

class Post < ApplicationRecord
  # title:string attribute
end

# Create Comment model with content and post reference
# Your code here

Need a hint?

Use rails generate model Comment content:string post:references to create the model with the correct attributes.

3

Add belongs_to association in Comment model

In the Comment model, add the line belongs_to :post to set up the association.

Ruby on Rails

class Post < ApplicationRecord
  # title:string attribute
end

class Comment < ApplicationRecord
  # content:string attribute
  # post:references attribute
  # Add belongs_to association here
  # Your code here
end

Need a hint?

Use belongs_to :post inside the Comment class.

4

Add has_many association in Post model

In the Post model, add the line has_many :comments to complete the two-way association.

Ruby on Rails

class Post < ApplicationRecord
  # title:string attribute
  # Add has_many association here
  # Your code here
end

class Comment < ApplicationRecord
  # content:string attribute
  # post:references attribute
  belongs_to :post
end

Need a hint?

Use has_many :comments inside the Post class.