Brahm

MVC architecture, an introduction

MVC architecture, an introduction

"By separating data (Model), presentation (View), and logic (Controller), MVC helps developers create modular, maintainable, and testable applications."

When software applications grow in complexity, organizing code efficiently becomes essential. Without structure, applications turn into spaghetti code, making maintenance and scaling difficult. To address this, developers use architectural patterns, and one of the most popular is MVC (Model-View-Controller).

MVC (Model-View-Controller) is a design pattern that helps developers separate concerns in an application. It divides an application into three interconnected components:
  •   Model – Manages data and business logic
  •   View – Handles UI and presentation
  •   Controller – Acts as a bridge between Model and View

  • The Model represents the data, rules, and business logic of an application. It:
  •   - Manages database operations (CRUD – Create, Read, Update, Delete)
  •   - Enforces business rules (e.g., validating user inputs)
  •   - Notifies the View when data changes

  • class User < ApplicationRecord
  validates :email, presence: true, uniqueness: true
end

Here, the User model ensures that every user has a unique email.

The View is responsible for displaying data to users. It:
  •  - Retrieves data from the Model
  •  - Formats and presents information
  •  - Does NOT contain business logic

<h1>Welcome, <%= @user.email %>!</h1>

Here, the View dynamically displays the user’s name but doesn’t manipulate data.

The Controller acts as an intermediary between the Model and View. It:
  •   - Accepts user input (HTTP requests)
  •   - Calls the appropriate Model for data processing
  •   - Sends processed data to the View for rendering

class UsersController < ApplicationController
  def show
    @user = User.find(params[:id])
  end
end

Here, the show action retrieves user data from the Model and passes it to the View.

How MVC Works Together: A Simple Flow
 - A user requests a webpage (e.g., /users/1).
- The Controller (UsersController) processes the request.
- The Model (User.find(params[:id])) fetches data from the database.
- The View (show.html.erb) displays the user’s information.


MVC provides a structured approach to building applications, making them easier to manage and scale. By separating data (Model), presentation (View), and logic (Controller), developers can create modular, maintainable, and testable applications.
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