MVC architecture overview in PHP - Step-by-Step Execution

Concept Flow - MVC architecture overview

User Request

↓

Controller receives request

↓

Controller processes input

↓

Controller calls Model

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Model handles data and logic

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Model returns data to Controller

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Controller sends data to View

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View renders output

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Response sent to User

The MVC flow starts with a user request handled by the Controller, which uses the Model for data and logic, then passes results to the View to create the output.

Execution Sample

PHP

<?php
// Controller receives request
class Controller {
  public function show() {
    $data = Model::getData();
    View::render($data);
  }
}
?>

This simple PHP code shows the Controller calling the Model to get data, then passing it to the View to display.

Execution Table

Step	Action	Component	Data/State	Output
1	User sends request	User	Request URL: /show	Request received by Controller
2	Controller receives request	Controller	Method: show()	Calls Model::getData()
3	Model processes data	Model	Fetch data from DB or logic	Returns data array ['name' => 'Alice']
4	Controller receives data	Controller	Data: ['name' => 'Alice']	Calls View::render(data)
5	View renders output	View	Data: ['name' => 'Alice']	HTML page with 'Hello, Alice!'
6	Response sent	System	Rendered HTML	User sees page
7	End	System	Request complete	Execution stops

💡 Request handled fully; response sent to user, execution ends.

Variable Tracker

Variable	Start	After Step 3	After Step 4	Final
request	null	/show	/show	/show
data	null	['name' => 'Alice']	['name' => 'Alice']	['name' => 'Alice']
output	null	null	null	HTML with 'Hello, Alice!'

Key Moments - 3 Insights

Why does the Controller call the Model before the View?

The Controller calls the Model first to get the data needed. Then it passes that data to the View to display. This order is shown in steps 3 and 4 of the execution table.

Does the View access the Model directly?

No, the View only receives data from the Controller. It does not call the Model. This separation keeps the code organized, as seen in step 5.

What happens after the View renders the output?

After rendering, the output is sent back to the user as a response, ending the request cycle. This is shown in step 6 and 7.

Visual Quiz - 3 Questions

Look at the execution table, at which step does the Model return data to the Controller?

A Step 4

B Step 3

C Step 5

D Step 2

💡 Hint

Check the 'Action' and 'Output' columns in step 3 where Model returns data.

At which step does the View create the HTML output?

A Step 2

B Step 4

C Step 5

D Step 6

💡 Hint

Look for 'View renders output' in the 'Action' column.

If the Controller skipped calling the Model, what would happen in the execution table?

A Data would be null or missing at step 4

B View would render normally with data

C User request would be sent twice

D Model would still send data automatically

💡 Hint

Refer to variable_tracker for 'data' variable changes after step 3 and 4.

Concept Snapshot

MVC Architecture Overview:
- Model: Manages data and logic
- View: Displays data to user
- Controller: Handles user input, calls Model, sends data to View
- Flow: User -> Controller -> Model -> Controller -> View -> User
- Keeps code organized and separates concerns

Full Transcript

MVC architecture divides a web app into three parts: Model, View, and Controller. When a user sends a request, the Controller receives it and processes input. The Controller calls the Model to get or update data. The Model handles data logic and returns results. The Controller then sends this data to the View. The View creates the HTML output shown to the user. This flow keeps the app organized and easier to maintain.