MVC (Model–View–Controller)

What is MVC (Model–View–Controller) in Ruby on Rails?

MVC (Model–View–Controller) is a software architecture pattern that organizes a Rails application into three interconnected components. Each component has a clear responsibility, making applications easier to build, understand, and maintain.

Rails follows MVC by default, which helps developers structure code in a predictable and scalable way.

Why is MVC Useful?

Without MVC, application code can become tightly coupled and difficult to manage. MVC helps by:

• Separating business logic from presentation

• Improving code readability and maintainability

• Making applications easier to test and scale

• Allowing multiple views to use the same data

• Enabling teams to work in parallel on different layers

How MVC Works?

In an MVC-based Rails application, a user request flows through the system in a structured way.

Key components:

• Model – Manages data, business rules, and database interactions.

• View – Handles how data is presented to the user.

• Controller – Processes user requests, interacts with models, and passes data to views.

Example

Model (post.rb):

class Post < ApplicationRecord 

    validates :title, presence: true
  
 end 

Represents and manages post data.

Controller (posts_controller.rb):

class PostsController < ApplicationController

  def index 
  
    @posts = Post.all
    
  end
  
end 

Fetches data and prepares it for display.

View (index.html.erb):

 <%= @posts.each do |post| %>

    <p><%= post.title %></p>
  
 <% end %> 

Displays the data to the user.

These examples show how models, controllers, and views work together to handle a user request.

Where to Use MVC?

• Structuring web applications in Rails

• Managing complex business logic

• Building scalable and maintainable systems

• Separating frontend and backend concerns

• Supporting collaborative development

In Summary

MVC is the foundation of Ruby on Rails architecture. By separating data, logic, and presentation, it makes applications easier to develop, maintain, and scale over time.