What do you know about the MVC pattern?

MVC (Model-View-Controller) is an architectural design pattern that divides an application into three interconnected parts:

• Model: Represents the application's data, business logic, rules, and constraints. Manages data from databases, file systems, or other sources. It is independent of the view and controller.
• View: Responsible for displaying data to the user and interacting with them. Receives data from the controller or directly from the model (in some implementations) and formats it for display. Contains no business logic.
• Controller: Handles user input, interacts with the model to update data, and selects the appropriate view to display the result. Acts as a link between the Model and the View.

Interaction between components typically occurs as follows:

1. The user interacts with the View.
2. The View sends a request to the Controller.
3. The Controller processes the request, interacts with the Model to retrieve or modify data.
4. The Model performs the necessary operations and notifies the Controller of changes (or the Controller requests updated data).
5. The Controller selects the appropriate View and passes it data from the Model.
6. The View displays the data to the user.

Advantages of MVC:

• Separation of concerns: Clear separation of logic, data, and presentation improves code organization.
• Reusability: The Model and Controller can be used with different Views.
• Improved testability: Separating components simplifies unit testing.
• Ease of maintenance: Changes in one part (e.g., only in the view) do not affect others.
• Parallel development: Different teams can work on the Model, View, and Controller simultaneously.

Example pseudocode:

// Controller
class UserController {
    private $userModel;  // Instance of Model

    public function __construct() {
        $this->userModel = new UserModel();
    }

    public function showUser($userId) {
        $user = $this->userModel->getUserById($userId);
        // Select the appropriate view
        include 'user_view.php'; // Assumes user_view.php displays the user
    }
    // Other controller methods for handling requests (create, delete, etc.)
}

// Model
class UserModel {
    public function getUserById($userId) {
        // Logic to retrieve user data from DB or other source
        // return array('id' => $userId, 'name' => 'User Name');
    }
    // Other model methods for working with user data (save, update, etc.)
}

// View (part of user_view.php)
// Assumes the variable $user is available in this file
// <h1>Hello, <?= $user['name'] ?>!</h1>
?>