edit_cart_list.php

<?php
// we will only start the session with session_start() IF the session isn't started yet //
if (session_status() == PHP_SESSION_NONE) {
    session_start();
}
?>

<?php
// including the conn.php to establish connection with database //
  include "conn.php";
?>

<?php
	$id = $_POST["id"];
	$text = $_POST["text"];
	$column_name = $_POST["column_name"];
	$sql = "UPDATE transaction_record SET ".$column_name."='".$text."' WHERE meal_id = '".$id."' AND order_id = '".$_SESSION["order_id"]."'";
	if(mysqli_query($con, $sql))
	{
		echo 'Notice: Meal ID: '.$id.'\'s quantity updated';
	}
 ?>