Multiple instances of an iten in a shopping cart

[tpiele]

Ok, first I am sorry for just dumping this here but I cannot think of what to search for to answer this one!

I have a shopping cart script that allows a user to select the color, size and quantity of a clothing item and put it in the shopping cart. When they hit submit it launches the form action to a script called addtocart.php which uses the code:

$buy = "INSERT INTO cart VALUES('$PHPSESSID', '$sku', '$qty', '$size', '$color')";

$buy_result = mysql_query($buy,$connect)
        or die ("Couldn't insert record!");

to insert the selected item. Size, color and quantity are posted to this script and I used $color = $_POST['color']; to yank it back out, above the insert, works great!

But I do not want the user to be able to go back a few minutes later and add the same thing again and have it show up on a diferent row in the cart. How can I check for an item already existing, say by the variable sku, and if it there either popup an error or just add the new quantity to the existing one? I'm lost! Thanks for any help, this board has helped me a lot so far!

Oh, if way wanna see my workspace go to www.morphosnaturals.com/catalog.php and click view all under the Health section, then add something to the cart....

[dalecosp]

Well, I won't be much help, I expect. I tend to keep the cart info within the session array, and you do it in the db (been some discussion in the EL recently on this....)

My strategy is to simply make sure that sku[$x] is not equal to sku[$x-1]; IOW, they didn't "refresh" the order link handler and add the item to the cart array a second time.

I kinda figure that if they do it on purpose, maybe they meant to. Perhaps in your case, you'd want to read the db, check for dupes, and then say, "you've already got one, sure you want another?"

Which brings us to the question ... what if they want a blue shirt in both XL and XXL? Should that be another row?

[Shrike]

To avoid users resubmitting with the reload button I did a header() redirect to another PHP page - reload then simply reloads the new PHP page (back button however no longer works 😉 )

[tpiele]

It's not the refresh button I am affraid of it is the user going back to like product.php?sku=sku and adding it again, and a 2nd row showing up in the cart for the same product. I'd like it to just update the qty and call it good. If they order a Blue XL and a blue XXL yes it should be on its own line. I send color and size to the addtocart page via $_POST

What I tried was a SELECT from cart where sku='$sku' and color='$color' and size='$size' ..... and then

$oldqty = $row["$qty"];

$newqty = $_POST['qty'] + $oldqty;
if num_rows > 0 {

$qwery = update cart set qty='$newqty' where sku='$sku';

} else {

Insert into cart yadda yadda...

where am I going wrong, this replaces the old qty with the post qty...

[Shrike]

What I tried was a SELECT from cart

select qty from cart

?

[tpiele]

I tried this and no luck... (syntax may not be perfect just typed it out, off to class. But the code in my actual page is correct syntax wise, but all it does is overright oldqty with $_POST['qty']; ideas?

$query = "SELECT sess, sku, color, size, qty from cart where sku='$sku ";
$query_result = mysql_query ($query);
num_records = @mysql_num_rows ($query_result);

$oldqty = $row['qty'];

if ($num_records > 0) {
$newqty = ($oldqty + $_POST['qty']);
$update = UPDATE cart SET qty='$newqty' where sku='$sku'";

	} else {
		insert statement
	}

[Shrike]

Originally posted by tpiele
I tried this and no luck... (syntax may not be perfect just typed it out, off to class. But the code in my actual page is correct syntax wise, but all it does is overright oldqty with $_POST['qty']; ideas?




$query = "SELECT sess, sku, color, size, qty from cart where sku='$sku ";
$query_result = mysql_query ($query);
num_records = @mysql_num_rows ($query_result);

$oldqty = $row['qty'];

if ($num_records > 0) {
$newqty = ($oldqty + $_POST['qty']);
$update = UPDATE cart SET qty='$newqty' where sku='$sku'";

	} else {
		insert statement
	} [/B][/QUOTE]

$query = "SELECT sess, sku, color, size, qty from cart where sku='$sku ";
$query_result = mysql_query ($query);
num_records = @mysql_num_rows ($query_result);
$row = mysql_fetch_assoc($query_result); //You missed this bit
$oldqty = $row['qty'];
...and so on...

[tpiele]

I get the following errors:

Warning: mysql_fetch_assoc(): supplied argument is not a valid MySQL result resource in /var/www/html/addtocart.php on line 36

Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/addtocart.php:36) in /var/www/html/addtocart.php on line 53

<?php

if (!$PHPSESSID) {
        header("Location: main.php");
        exit;
}
if (!($sku)) {
        header("Location: main.php");
        exit;
}

session_start();

if ((!$PHPSESSID) || (!$item_count_total)) {
        session_register("item_count_total");
}
if (!$item_count_total) {
        $item_count_total = "0";
}

$connect = mysql_connect("127.0.0.1", "xxxxx", "pissword")
  	or die ("Couldn't Connect to server.");

$qty = 1;

$db = mysql_select_db("xxxxxxx_com_-_db", $connect)
	or die ("Couldn't Select database.");

$size = $_POST['sizebox']; 
$color = $_POST['colorbox'];
$qty = $_POST['qty'];

$query = "SELECT sess, sku, color, size, qty from cart where sku='$sku "; 
$query_result = mysql_query ($query); 
$num_records = @mysql_num_rows ($query_result); 

$row = mysql_fetch_assoc($query_result); 
$oldqty = $row['qty']; 

if ($num_records > 0) { 
$newqty = ($oldqty + $qty); 
$update = "UPDATE cart SET qty='$newqty' where sku='$sku'"; 

} else { 

$buy = "INSERT INTO cart VALUES('$PHPSESSID', '$sku', '$qty', '$size', '$color')";

$buy_result = mysql_query($buy,$connect)
        or die ("Couldn't insert record!");
}

$item_count_total = $item_count_total + $qty;

header("Location: cart.php");
exit;
?>

[enterume]

I just complete a shopping cart which let the user select the quantity of the item, and I calculate the amount and total according to the number of item they select.

What i do is, I store the value as multi-dimension(depends on the value you want to save), in SESSION(). In session, you can set the time that the server will keep it, or you manually remove it using session_unregister(), after some time.

It would be more simple and quicker to get the result and show in your shopping cart. YOu can save the step get the result from your database.

Just to share my experinece here.

🆒

[tpiele]

and how does that not allow them to add a second instance of the same item and have it displayed on its own row in the cart? I do pass the info via sessions except color and size, as it is just easier to dump it in POST for a few seconds and then insert it into the DB on the fly....

[enterume]

If you want to avoid the user store a duplicate item into the cart, before you save into the item to your cart, you can check with yoru sessions whether the product ID/ NAME alreadly exists. IF yes, then show some error message to them; ELSE, proceed to save it.