multiple table issue

[eluser]sith4life[/eluser]
the following checks to see if the update button is pressed

Code:

if($this->input->post('update'))
        {
            $this->Products_model->update_cart($this->input->post('cart_id'),$this->input->post('qty'));
        }

if so run this query

Code:

function update_cart($id,$qty,$delete = false)
    {
        if($delete === false)
        {
            $query = '
            UPDATE carts
            SET carts.qty = "'.$qty.'"
            WHERE carts.id = "'.$id.'"
            ';
        }
        else
        {
            $query = '
            DELETE FROM carts
            WHERE carts.id = "'.$id.'"
            ';
        }
        $this->db->query($query);
    }

EXCEPT. $id is being populated with the products.id (or carts.product_id) and not the carts.id field so the query just returns with no rows affected.
$id is passed from a hidden field with the value set to what is supposed to be the correct ID, but it's not.

Code:

echo form_open('store/cart');
                    $options = array('name' => 'qty','value' => $cart->qty, 'maxlength' => '3', 'size' => '2');
                    echo form_input($options);
                    echo form_hidden('cart_id',$cart->id);
                    echo form_submit('update','Update Quantity');
                    echo form_close();

Here is the ENTIRE Products_model.php file

Code:

<?php

class Products_model extends CI_Model {
    
    function __construct()
    {
        // Call the Model constructor
        parent::__construct();
    }
    
    function get_all_products()
    {
        $query = $this->db->query('SELECT * FROM products');
        return $query->result();
    }

    function add_to_cart($info)
    {
        $result = $this->db->insert('carts',$info);
        if($result)
         {
             return true;
         }
         else
         {
             return false;
         }
    }
    function view_cart($email)
    {
        $query = $this->db->query('SELECT carts.*, products.* FROM carts, products WHERE carts.product_id = products.id');
        return $query->result();
    }
    /*
     * takes 2 parameters id, qty and 1 optional
     * boolean, delete
     *
     * if delete is set the item is deleted from the table
     * otherwise update the qty field for the select cart item
     *
     *
     */
    function update_cart($id,$qty,$delete = false)
    {
        if($delete === false)
        {
            $query = '
            UPDATE carts
            SET carts.qty = "'.$qty.'"
            WHERE carts.id = "'.$id.'"
            ';
        }
        else
        {
            $query = '
            DELETE FROM carts
            WHERE carts.id = "'.$id.'"
            ';
        }
        $this->db->query($query);
    }
    function add_product($info)
    {
         $result = $this->db->insert('products',$info);
         if($result)
         {
             return true;
         }
         else
         {
             return false;
         }
    }

}