SESSION-

A session contains user information on server side. When a user opens a page, then the information is first transferred to the server, then php will match that information to the server-side cookie.

If the browser is closed once, all the data in the session will be lost. On re-opening the browser a new session will start. To maintain the data $_SESSION super global variable is used.

Advantages-

• Ability to store large amount of data.
• Secure because data is stored on the server side.
• Can store objects and string both.

Disadvantages-

• All data is lost when browser is closed.
• Depend on cookie.

Creating a session:

<?php session_start(); ?>

Setting value:

<?php $_SESSION[first_name] = Neha; ?>

Reading value:

<?php echo $_SESSION[first_name]; ?>

Removing data:

<?php unset($_SESSION[first_name]); ?>

Ending session:

<?php session_destroy(); ?>

COOKIE-

A cookie contains user information in the client side. $_COOKIE superglobal stores the value, which is read by the php.

There is no need to store cookie, it remains stored in our system.

Advantages-

• Cookie remains stored if the browser is closed.

Disadvantages-

• Limited amount of data can be stored.
• Stored in client side, so user can view it.

Creating a cookie:

<?php
    if (!isset($_COOKIE['Ordering'])) {
        setcookie("Ordering", $_POST['ChangeOrdering'], time() + 31536000);
    }
?>

Using a cookie:

<?php
    echo (isset($_COOKIE[ordering])) ? $_COOKIE[ordering] : cookie value not set;
?>

Deleting a cookie:

<?php setcookie(favorite_color); ?>