Transferring order values from php shopping cart to MySQL

Question

I am trying to setup a “checkout/order” page within a site in which logged in users earn points/credits. Once they earn a certain amount of these points they can then go to a shopping cart and pay with these points only. (No money changes hands, so no paypal/checkout/shipping/taxes etc are involved).

I have done a 'shopping cart' page and 'view cart' page (view cart code is on this page), which works fine thanks to Steve and KMK ;).

I have two tables on my MySQL database, 'orders' (which has order id, users id, total & time stamp) and 'order_contents' (order contents id, order id, product id, quantity and price). 'total' is total price, 'price' is price per product.

I am trying to get the items that the user selects (ie products, quantity etc) from the view cart page into the 'order' and 'order_contents' tables in the database via the submit_cart.php file (code below) but it isn't working properly.

What does work on this code is that it puts a new row/order_id into the orders table, as well as the users_id.

What doesn't work: The total price of the order doesn't get inserted (shows up as '0' on the database) and it displays the first error message (with the 1 on the end).

Nothing gets inserted into the 'order_contents' table either, at this point I am assuming it is because the insert into the 'orders' table isn't working or somehow the cart session variables are not going across(?) but I am happy to be corrected...

If someone could lend a hand or even suggest a different approach please feel free! Thanks!

<?php 
$page_title = 'Order Confirmation';
include ('./includes/header.html');

if (!isset($_SESSION['users_id'])) {

   // Start defining the URL.
   $url = 'http://' . $_SERVER['HTTP_HOST']
    . dirname($_SERVER['PHP_SELF']);
   // Check for a trailing slash.
   if ((substr($url, -1) == '/') OR (substr($url, -1) == '\\') ) {
        $url = substr ($url, 0, -1); // Chop off the slash.
   }
   // Add the page.
   $url .= '/login.php'; 

ob_end_clean(); // Delete the buffer.
header("Location: $url"); 
exit(); // Quit the script.
}

$users = $_SESSION['users_id']; // Temporary.

$total = 0; // Total cost of the order.

require_once ('/MySQL/database.php'); // Connect to the database.

@mysqli_autocommit ($dbc, FALSE);

$query = "INSERT INTO orders (users_id, total) VALUES
   ($users, $total)";
$result = @mysql_query($query);
if (@mysql_affected_rows($dbc) == 1) {

// Need the order ID.
$oid = @mysql_insert_id($dbc);

// Insert the specific order contents into the database.
$query = "INSERT INTO order_contents (order_id, products_id, quantity, price)
   VALUES (";foreach ($_SESSION['cart'] as $pid =>$value) {
$query .= "$oid, $pid, {$value['quantity']}, {$value['price']})";
}
$query = substr($query, 0, -2); // Chop off last two characters.
$result = @mysql_query($query);

// Report on the success.
if (@mysql_affected_rows($dbc) == count($_SESSION['cart'])) { // Whohoo!

// Commit the transaction.
@mysqli_commit($dbc);
@mysql_close($dbc);

// Clear the cart.
unset($_SESSION['cart']);

// Message to the customer.
echo '<p>Thank you for your order.
   It has been submitted for processing.</p>';

// Send emails and do whatever else.

} else { // Rollback and report the problem.

@mysqli_rollback($dbc);
@mysql_close($dbc);

echo '<p>Your order could not be processed due to a system error.
   You will be contacted in order to have the problem fixed.
   We apologize for the inconvenience 1.</p>';
// Send the order information to the administrator.

}

} 

else { // Rollback and report the problem.

@mysqli_rollback($dbc);
@mysql_close($dbc);

echo '<p>Your order could not be processed due to a system error.
   You will be contacted in order to have the problem fixed.
   We apologize for the inconvenience 2.</p>';
// Send the order information to the administrator.
}

?>
</div></div>

<?php  
include ('./includes/footer.html');
?>

Answer 1

Here's a really simple example that uses stored procedures which you might find useful.

Full script here : http://pastie.org/1268992

Hope it helps :)

Example stored procedure calls

start transaction;

call insert_order(1);

call insert_order_item(1,1,2);
call insert_order_item(1,2,4);
call insert_order_item(1,3,6);

commit;

Example PHP script

<?php

// dummy session data

$userID = 1; 

$cart = array(
    array("product_id" => 1, "qty" => 2, "item_id" => 0, "price" => 0, "subtotal" => 0), 
    array("product_id" => 2, "qty" => 4, "item_id" => 0, "price" => 0, "subtotal" => 0),    
    array("product_id" => 3, "qty" => 6, "item_id" => 0, "price" => 0, "subtotal" => 0));

$conn = new mysqli("localhost", "foo_dbo", "pass", "foo_db", 3306);

try{
    $conn->autocommit(FALSE); // start transaction

    // create the order 

    $sql = sprintf("call insert_order(%d)", $userID);

    $result = $conn->query($sql);
    $row = $result->fetch_array();
    $result->close();

    $orderID = $row["order_id"]; //  new order_id returned by sproc
    $conn->next_result();   

    // loop your cart and insert order items

    foreach($cart as $k => $v){

        $sql = sprintf("call insert_order_item(%d,%d,%d)", $orderID, $v["product_id"],$v["qty"]);

        $result = $conn->query($sql);
        $row = $result->fetch_array();
        $result->close();

        $cart[$k]["item_id"] = $row["item_id"]; // save data returned by sproc incase you need it ??
        $cart[$k]["price"] = $row["price"];
        $cart[$k]["subtotal"] = $row["subtotal"];

        $conn->next_result();   
    }
    $conn->commit(); //all OK so commit order/order items...

    echo sprintf("your order no. is %s<br/>", $orderID);

    $total = 0;
    foreach($cart as $k => $v){
        $total += $v["subtotal"];
        echo sprintf("item_id=%s, product_id=%s, price=%s, qty=%s, subtotal=%s<br/>", 
            $v["item_id"],$v["product_id"],$v["price"],$v["qty"],$v["subtotal"]);
    }
    echo sprintf("order total = %s<br/>", $total);

}
catch(exception $ex){
    //handle errros and rollback
    $conn->rollback();
    echo sprintf("order error - %s<br/>", $ex->getMessage()); 
}

$conn->close();
?>

Example MySQL script

-- TABLES

drop table if exists users;
create table users
(
user_id int unsigned not null auto_increment primary key,
username varbinary(32) unique not null
)
engine=innodb;

drop table if exists products;
create table products
(
product_id smallint unsigned not null auto_increment primary key,
name varchar(255) unique not null,
price decimal(10,2) not null default 0
)
engine=innodb;

drop table if exists orders;
create table orders
(
order_id int unsigned not null auto_increment primary key,
user_id int unsigned not null,
order_date datetime not null,
total decimal(10,2) not null default 0,
key (user_id)
)
engine=innodb;

drop table if exists order_items;
create table order_items
(
item_id int unsigned not null auto_increment primary key,
order_id int unsigned not null,
product_id smallint unsigned not null,
qty smallint unsigned not null default 0,
price decimal(10,2) not null default 0,
subtotal decimal(10,2) not null default 0,
key (order_id),
key (product_id)
)
engine=innodb;

-- STORED PROCEDURES

drop procedure if exists insert_order;

delimiter #

create procedure insert_order
(
in p_user_id int unsigned
)
proc_main:begin

declare v_order_id int unsigned default 0;

    insert into orders (user_id, order_date, total) values (p_user_id, now(), 0);

    set v_order_id = last_insert_id();

    -- do more things with v_order_id ??

    select v_order_id as order_id;

end proc_main #

delimiter ;

drop procedure if exists insert_order_item;

delimiter #

create procedure insert_order_item
(
in p_order_id int unsigned,
in p_product_id smallint unsigned,
in p_qty smallint unsigned
)
proc_main:begin

declare v_item_id int unsigned default 0;
declare v_price decimal(10,2) default 0;
declare v_subtotal decimal(10,2) default 0;

    select price into v_price from products where product_id = p_product_id;

    set v_subtotal =  v_price * p_qty;

    insert into order_items (order_id, product_id, qty, price, subtotal) values 
        (p_order_id, p_product_id, p_qty, v_price, v_subtotal);

    set v_item_id = last_insert_id();

    -- do more things with v_item_id ??

    update orders set total = total + v_subtotal where order_id = p_order_id;

    select p_order_id as order_id, v_item_id as item_id, 
        v_price as price, v_subtotal as subtotal;

end proc_main #

delimiter ;

-- TEST DATA

insert into users (username) values ('f00'),('bar'),('alpha'),('beta'),('gamma');
insert into products (name, price) values ('product 1', 9.99),('product 2',12.34),('product 3',32.50),('product 4',1.99);

Answer 2

you have set the total variable to 0 thats why the total cost on the order table shows zero.

$total = 0; // Total cost of the order.