MVC architecture in Laravel - Step-by-Step Execution

Concept Flow - MVC architecture in Laravel

User Request

↓

Routes

↓

Controller

↓

Model

↓

View

↓

Response to User

This flow shows how a user request moves through Laravel's MVC: routes direct to controllers, which use models to get data, then pass it to views for display.

Execution Sample

Laravel

<?php
// Route
Route::get('/users', [UserController::class, 'index']);

// Controller
class UserController extends Controller {
  public function index() {
    $users = User::all();
    return view('users.index', ['users' => $users]);
  }
}

This code handles a user request to '/users', fetches all users from the database via the model, and sends data to the view for display.

Execution Table

Step	Action	Component	Data/State	Output/Next Step
1	User visits '/users' URL	User	Request: GET /users	Route matches '/users'
2	Route calls controller method	Route	Calls UserController@index	Controller method invoked
3	Controller fetches all users	Controller	Calls User::all()	Receives collection of users
4	Model queries database	Model	Executes SQL SELECT * FROM users	Returns collection of users
5	Controller passes data to view	Controller	Data: users collection	View 'users.index' rendered with data
6	View generates HTML	View	Renders user list HTML	HTML sent as response
7	Browser receives HTML	User	Displays user list page	User sees list of users
8	End of request cycle	System	No further action	Request complete

💡 Request cycle ends after view renders and response is sent to user

Variable Tracker

Variable	Start	After Step 3	After Step 4	After Step 5	Final
users	undefined	Collection of User objects	Collection of User objects	Passed to view	Used in HTML output

Key Moments - 3 Insights

Why does the controller call the model instead of querying the database directly?

The controller uses the model to keep code organized and separate data logic from request handling, as shown in step 3 and 4 of the execution table.

How does the view get the data it needs to display?

The controller passes the data to the view as variables (step 5), so the view can use it to generate HTML (step 6).

What role do routes play in MVC?

Routes connect user URLs to controller methods, directing the flow of the request as seen in step 2.

Visual Quiz - 3 Questions

Look at the execution table, at which step does the model query the database?

A Step 4

B Step 5

C Step 3

D Step 2

💡 Hint

Check the 'Component' and 'Action' columns in the execution table for database queries.

According to the variable tracker, what is the state of 'users' after step 4?

A Array of user data from DB

B Collection of User objects

C Undefined

D Passed to view

💡 Hint

Look at the 'After Step 4' column for the 'users' variable in the variable tracker.

If the route did not exist for '/users', what would happen in the execution flow?

A Controller would still be called

B View would render empty data

C Request would stop at routing with an error

D Model would query database anyway

💡 Hint

Refer to step 2 in the execution table where the route directs the request.

Concept Snapshot

MVC in Laravel:
- Route receives user URL and directs to Controller
- Controller handles logic and calls Model for data
- Model interacts with Database
- Controller sends data to View
- View renders HTML for user
Keep these parts separate for clean code.

Full Transcript

In Laravel's MVC architecture, a user request starts at the routes which map URLs to controller methods. The controller acts like a middleman, asking the model to fetch data from the database. The model runs the database queries and returns data. The controller then passes this data to the view, which creates the HTML page the user sees. This separation keeps code organized and easy to manage. The execution table shows each step from user request to response, and the variable tracker follows how data changes. Key moments clarify why controllers use models and how views get data. The quiz tests understanding of these steps.