Session vs cookie decision in PHP - Visual Side-by-Side Comparison

Concept Flow - Session vs cookie decision

Start

↓

Need to store user data?

↓

No storage needed

→End

Yes↓

Is data sensitive?

↓

Use Session (server-side)

→End

No↓

Need data to persist after browser closes?

↓

Use Cookie (client-side)

→End

No↓

Use Session (temporary, server-side)

→End

Decide whether to use session or cookie by checking if data is sensitive and how long it should persist.

Execution Sample

PHP

<?php
session_start();
if ($isSensitive) {
  $_SESSION['user'] = $userData;
} else {
  setcookie('user', $userData, time() + 3600);
}
?>

Stores user data in session if sensitive, otherwise in a cookie for 1 hour.

Execution Table

Step	Condition Checked	Condition Result	Action Taken	Storage Type
1	Need to store user data?	Yes	Check if data is sensitive	None yet
2	Is data sensitive?	Yes	Store in session	Session (server-side)
3	End	-	Data stored securely on server	Session (server-side)

💡 Data stored securely in session because it is sensitive.

Variable Tracker

Variable	Start	After Step 2	Final
$isSensitive	true	true	true
$_SESSION['user']	unset	set to userData	set to userData
setcookie('user')	unset	not set	not set

Key Moments - 2 Insights

Why do we use session for sensitive data instead of cookies?

Sessions store data on the server, so sensitive info is not exposed to the user, as shown in execution_table step 2.

What happens if data is not sensitive and needs to persist after browser closes?

Cookies are used because they stay on the client even after closing the browser, unlike sessions which end, as explained in concept_flow.

Visual Quiz - 3 Questions

Look at the execution_table, what storage type is chosen when data is sensitive?

A Session (server-side)

B Cookie (client-side)

C Local storage

D No storage

💡 Hint

Check execution_table row 2 under 'Storage Type'

At which step does the program decide to store data in session?

A Step 1

B Step 2

C Step 3

D No step

💡 Hint

Look at execution_table 'Action Taken' column for step 2

If $isSensitive was false and data should persist after browser closes, what would change?

A Data stored in session

B Data stored in cookie

C No data stored

D Data stored in local storage

💡 Hint

Refer to concept_flow decision after 'Is data sensitive?' and 'Need data to persist after browser closes?'

Concept Snapshot

Session vs Cookie Decision:
- Use session for sensitive data (stored server-side).
- Use cookie for non-sensitive data needing persistence after browser closes.
- Sessions expire when browser closes; cookies can last longer.
- Sessions keep data hidden from user; cookies are stored on user device.
- Choose based on sensitivity and persistence needs.

Full Transcript

This visual execution shows how to decide between using sessions and cookies in PHP. First, check if you need to store user data. If yes, check if the data is sensitive. Sensitive data should be stored in sessions because sessions keep data on the server, protecting it from user access. If data is not sensitive and needs to persist after the browser closes, use cookies because they stay on the user's device. The example code stores user data in session if sensitive, otherwise in a cookie for one hour. The execution table traces these decisions step-by-step, showing when and where data is stored. Key moments clarify why sessions protect sensitive data and when cookies are better for persistence. The quiz tests understanding of these decisions based on the visual trace.