AddItem function does not seem to be working - php

Question

I go this thing to sorta work but my AddItem function doesn't seem to work. I click the "add item" link on the products page and it takes me to the cart page. But nothing is on the cart page. I am hoping somoneone can see it and tell me what to do to correct it.
The AddItem function:
function AddItem($itemId, $qty) {
// Will check whether or not this item
// already exists in the cart table.
// If it does, the UpdateItem function
// will be called instead
// Check if this item already exists in the users cart table
$result = mysql_query("select count(*) from cs368_cart where cookieID = '" . GetCartID() . "' and itemId = $itemId");
$row = mysql_fetch_row($result);
$numRows = $row[0];
if($numRows == 0) {
// This item doesn't exist in the users cart,
// we will add it with an insert query
mysql_query("insert into cs368_cart(cookieID, itemId, qty) values('" . GetCartID() . "', $itemId, $qty)");
}
else {
// This item already exists in the users cart,
// we will update it instead
UpdateItem($itemId, $qty);
}
}
I just checked my cs368_cart tables of the database and it is empty.
mysql> select * from cs368_cart
-> ;
Empty set (0.00 sec)
So apparently nothing is being added. I am wondering if my query is correct?
My tables:
mysql> select * from cs368_products
-> ;
+--------+----------------+---------------------------------------------+-----------+
| itemId | itemName | itemDesc | itemPrice |
+--------+----------------+---------------------------------------------+-----------+
| 1 | French Vanilla | A medium blend with a hint vanilla | 9.79 |
| 2 | Hazelnut Cream | A light blend with a spicy note of Hazelnut | 9.69 |
| 3 | Columbian | A medium-dark blend straight up | 9.89 |
+--------+----------------+---------------------------------------------+-----------+
3 rows in set (0.00 sec)
and my cart tables;
mysql> show columns from cs368_cart;
+----------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+----------------+
| cartId | int(11) | NO | PRI | NULL | auto_increment |
| cookieId | varchar(50) | NO | | | |
| itemId | int(11) | YES | | NULL | |
| qty | int(11) | YES | | NULL | |
+----------+-------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)
This is my GetCartId I have in a seperate php file which is bieng called correctly by the php file with this AddItem function.
function GetCartId(){
if(isset($_COOKIE["cartId"])){
return $_COOKIE["cartId"];
}
else {
session_start();
setcookie("cartId", session_id(), time()+((3600*24)*30));
return session_id();
}

Answer 1

It looks like you are trying to insert cartId as a string when your table has cartId as an integer. Take a closer look at your SQL in the PHP strings.

Answer 2

You should change your insert query to something similar to below which will tell you what is wrong with your insert sataement (also it is good practice to handle any errors gracefully)
<?php
$queryResult = mysql_query("insert into cs368_cart(cookieID, itemId, qty) values('" . GetCartID() . "', $itemId, $qty)");
if (!$queryResult) {
die('Invalid query: ' . mysql_error());
}
?>
based on example in http://php.net/manual/en/function.mysql-query.php