Introduction

The Model-View-Controller (MVC) architecture is a fundamental design pattern in Ruby on Rails. It separates the application into three interconnected components, making the development process more organized and manageable.

Model

The Model represents the application's data and business logic. In Rails, models are typically ActiveRecord classes that map to database tables.

• Data Management: Models handle the data interactions, including CRUD operations (Create, Read, Update, Delete).
• Business Logic: Models contain the core logic and rules that define how data can be manipulated and accessed.

# Example model definition in Rails
class User < ApplicationRecord
  validates :name, presence: true
  has_many :posts
end
                

View

The View is responsible for displaying the data to the user. It generates the HTML, CSS, and JavaScript that make up the user interface.

• Presentation Layer: Views render the data provided by the controller in a user-friendly format.
• Templates: Rails uses embedded Ruby (ERB) templates to combine Ruby code with HTML.

<%= @user.name %>
Email: <%= @user.email %>
                

Controller

The Controller acts as the intermediary between the Model and the View. It processes incoming requests, interacts with the model, and renders the appropriate view.

• Request Handling: Controllers receive HTTP requests and determine how to handle them.
• Data Interaction: Controllers interact with the model to retrieve or manipulate data.
• View Rendering: Controllers render the appropriate view based on the request and data obtained from the model.

# Example controller in Rails (app/controllers/users_controller.rb)
class UsersController < ApplicationController
  def show
    @user = User.find(params[:id])
  end
end
                

How MVC Works Together

In a typical Rails application, a user's request flows through the MVC components as follows:

• Request: The user makes a request to the server (e.g., via a URL).
• Controller: The request is routed to the appropriate controller action.
• Model: The controller interacts with the model to retrieve or manipulate data.
• View: The controller passes data to the view, which renders the final output as HTML.
• Response: The rendered HTML is sent back to the user's browser.

Conclusion

Understanding the MVC architecture is essential for developing applications with Ruby on Rails. It promotes a clean separation of concerns, making the codebase easier to manage and scale. By following the MVC pattern, you can build robust and maintainable web applications.