Important SQL functions

mysqli_insert_id

Function mysqli_insert_id($conn) returns the ID of the record just inserted into the Database

array_key_exists(<key>, <array>)

You must pass the key you're searching for, and the array you want to search as parameters to function array_key_exists(). This function returns a true or false. For example:

<?php

session_start();
if (array_key_exists("uname", $_COOKIE)){

$_SESSION["uname"] = $_COOKIE["uname"]

};

?>