2025-09-29_creating a session in php

// check if php session has started
// 1. first and best method
if(session_id() == '') session_start();
// if session is not started, session id will be empty.

// 2. second method
if(!isset($_SESSION)) session_start();
// if session is not set it should be started.

// 3. Third method
if( !defined( 'SID' ) ) session_start();
// start session if session id is not defined.