1) Set the data type for the date field to use date rather than timestamp. the use the following code to insert the correct date:
<?php echo(date("Y-m-d")); ?>
2) does the registration page have an authenticate user behavior on it that automatically logs them in?
create the link to the registration page as:
<a href="regitration.php?accesscheck=<?php echo (htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES)); ?>">register</a>
and on the registration form, make sure the action passes any query string variables that are passed in:
action="<?php echo (htmlentities($_SERVER["PHP_SELF"], ENT_QUOTES)); ?><?php echo (isset($_SERVER["QUERY_STRING"]) && $_SERVER["QUERY_STRING"] != ""?"?".htmlentities($_SERVER["QUERY_STRING"], ENT_QUOTES):""); ?>"
3) Each shipping address should be a unique record. I'm assuming that in your users table, you have a column that links to the default shipping address by storing the ID for that record?
the radio buttons value should use the ID for the shipping address records, and on submit it should update the relation column in the users table.
4) you should be storing the ID of the logged in user in the orders table, and use a join query to return the billing address rather than storing it in the orders table.
5) use the following code to display total quantity:
<?php echo $cartName->TotalColumn("Quantity"); ?>
6) You would need to use an SQL COUNT statement to return the numbers of records that belonged to the category: