[RESOLVED] Need help matching a product ID with it's POST partner.

schwim

Hi there everyone,

I'm trying to work through an order form. On the page in which the client chooses the products they wish to order, the order form is generated by a while loop which creates a form with input boxes for the quantity they wish to order. When they click submit, they are sent to the order submission page, on this page, I need to loop through all the products in the database, and check to see if that product has a $_POST['thatproductid'] with a quantity of !=1. If so, I need to store the ordered product in the database.

I've come to the conclusion that I need an identical while loop on the order submission page, but I don't know how to match that $id with it's $_POST brethren. If anyone has an idea of how I would handle this, I would very much appreciate your help!

Weedpacket

If you name the fields like this:

<input name="product[$id]['qty']" />
<input name="product[$id]['thingy']" />
...

Then on submission all the product fields would be in a single array $POST['product'], and all the field values for product 42 would be in a single array $POST['product'][42].

Is this the sort of matching you're after?

schwim

Hi there weedpacket and thanks very much for your help.

I think I can see where that would help, but do you have an idea how I would tell it to update that product in the database? I think I'll need this:

            /*Go through the products in the database and check for a matching POST ['product'] with a qty of 1 or more.*/
            $query="SELECT * FROM products";
            $result=mysql_query($query) or die (mysql_error());
            $numr=mysql_num_rows($result);
            if($numr!=0){
                while($row=mysql_fetch_array($result)){
                    $id=$row['id'];
                   !!! I need to find the matching POST id and check for a number other than 0.  If it exists, add the item to the products_ordered table. !!!
                }
            }

Do you have an idea of how I would do this? Would it be some kind of explode function?

bradgrafelman

Why on earth would you loop through the DB and check if such an item was POST'ed? If you had 1 million items in the DB, and only 1 item was POST'ed, then your script would have to sit there and waste time checking for 999,999 items that don't exist.

Why not just loop through the POST'ed data and perform the necessary SQL queries?

schwim

Hi there Brad,

I do what I do usually because of ignorance. I couldn't figure out a way to check for the presence of each item except by manually writing the code to check for the existence of posted data for each product in the database. Since the product listing would change, that wouldn't really work.

If you know how I could loop through the post data without having to write an if statement for each product to check for it's existence, I would very much appreciate the help 🙂

thanks,
json

bradgrafelman

Assuming you're using the structure Weedpacket proposed above, simply do a [man]foreach/man loop over the multi-dimensional array $_POST['product'].

schwim

Could you show me an example of how that might work? I've read the page for foreach, but in each example, the array is being set by manually setting it's value in the code. I don't know how to grab the values(or I guess what I mean is the min and max limits) of the data being passed.

bradgrafelman

The usage doesn't change...

foreach($whateverArrayYouWant as $key => $value)

where in your case, $value would be an array (with keys such as 'qty' and 'thingy' according to Weedpacket's sample HTML elements above).

schwim

Since I don't understand the usage at all, I'll take my best shot at this and would appreciate any help on corrections that need to be made.

I've altered the quantity boxes on my form to the following:

<input type='text' size='5' maxlength='5' name=\"product[$id]['qty']\">

foreach ($_POST['product'] as $id) {
    $query="INSERT INTO products_ordered (order_id,product_id,quantity) VALUES ('$order_id','$id','$qty')";
		$results=mysql_query($query) or die(mysql_error());
}

Even not understanding this at all, I can see that this is screwed up. Will $id and $qty already be defined by the foreach?

bradgrafelman

The only thing that is "defined" by the foreach is whatever variable(s) you have after the 'as' keyword.

Since the 'id' of the product is used as the key of the array, you'll want to use foreach()'s other syntax - the '$id => $value' syntax (as shown above).

Whatever you call $value will then be an array containing the desired data, e.g. $value['qty'] etc.

schwim

Does this work, Brad?

foreach ($_POST['product'] as $id => $product) {
    $qty=$product['qty'];
    $query="INSERT INTO products_ordered (order_id,product_id,quantity) VALUES ('$order_id','$id','$qty')";
		$results=mysql_query($query) or die(mysql_error());
}

I'm sort of confused how this will know when to use the value contained in the post data to populate 'qty'. It's getting the id value from the name of the input, will it also get the value for qty from the name, giving me a value of 'qty' for 'qty'?

If this is correct, then could I ask another question? How does this code know which value to set as id? Is it because ID comes first in the input and the key is always in the first position?

bradgrafelman

I don't see where $order_id is coming from... was it defined elsewhere?

Also, you should never place user-supplied data directly into a SQL query, else your code will be vulnerable to SQL injection attacks and/or just plain SQL errors. Instead, you must first sanitize the data with a function such as [man]mysql_real_escape_string/man (for string data).

As far as your other questions go... perhaps you should do a [man]print_r/man on $_POST['products'] to see the structure of the multi-dimensional array you're using.

schwim

Hi there Brad,

$order_id is being defined prior to the individual products being placed into the database during an order's master record being created.

I'm going to sanitize the input but was only trying to get the foundation to build off of correct. Unfortunately, I think I've messed up somewhere because I'm getting an error:

Warning: Invalid argument supplied for foreach() in /home/schwim5/public_html/phoenixhill.net/orders/index.php on line 165

This is my foreach:

			foreach ($_POST['product'] as $id => $product) {
				$qty=$product['qty'];
				if($qty>=1){
					$query="INSERT INTO products_ordered (order_id,product_id,quantity) VALUES ('$order_id','$id','$qty')";
					$results=mysql_query($query) or die(mysql_error());
				}
			}

I imagine I'm just messing up the structure and would appreciate any insight. Thanks very much for all your help.

bradgrafelman

Sounds like $POST['product'] isn't an array. You can verify this by doing a [man]print_r/man on the $POST array to see what it contains.

schwim

Hi there Brad,

print_r helped me find the problem. I had escaped the quotes in Weedpacket's naming convention improperly. I fixed that and print_r seems to show a proper setup:

Array ( [3] => Array ( ['qty'] => ) [2] => Array ( ['qty'] => ) [4] => Array ( ['qty'] => ) [1] => Array ( ['qty'] => ) [19] => Array ( ['qty'] => ) [18] => Array ( ['qty'] => ) [10] => Array ( ['qty'] => ) [11] => Array ( ['qty'] => ) [12] => Array ( ['qty'] => ) [15] => Array ( ['qty'] => ) [13] => Array ( ['qty'] => ) [14] => Array ( ['qty'] => ) [9] => Array ( ['qty'] => ) [8] => Array ( ['qty'] => ) [20] => Array ( ['qty'] => ) [16] => Array ( ['qty'] => ) [17] => Array ( ['qty'] => ) [6] => Array ( ['qty'] => ) [5] => Array ( ['qty'] => 10 ) [7] => Array ( ['qty'] => 20 ) )

You can see that the last two objects in the array have a quantity of 10 & 20, respectively. For some reason however, my loop still did not enter the objects into the database and I received no error of the mysql statement, so I'm assuming that I've set up the loop incorrectly. What I thought I did was set it up to insert a record if the qty was 1 or more. Can you see any reason why it wouldn't insert a record for the final two objects in the array or do you know how I could check?

[EDIT]echoing $qty in the foreach loop shows a null value, so I'm not populating the variable correctly. is " $qty=$product['qty']; " the wrong way to get this value?[/EDIT]

bradgrafelman

Can you show us what your HTML now looks like?

Also, you can add a print_r() inside the foreach() loop to see what $product looks like. While doing so, note that you'll either want to a) view the source of the page, or b) wrap the print_r() output in '<pre>..</pre>' HTML tags. This preserves the whitespace in the output and makes it much easier (for you and us) to read.

schwim

Hi there Brad,

Here's what one of my inputs now looks like:

<input type='text' size='5' maxlength='5' name="product[12]['qty']"'>

here's what $product looks like in the loop:

(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] =>
)
Array
(
['qty'] => 10
)
Array
(
['qty'] => 20
)

So, I can see that the array is no longer printing the id. Is this my problem?

schwim

I just wanted to mention that I got rid of the errant single quote in the input but the result was the same.

schwim

I've updated the print_r of the array. The initial post was in error, as I was still getting the information from the print_r outside of the loop.

bradgrafelman

So what does your HTML now look like? Above, your index wasn't named qty it was named 'qty' (with single quotes on either side), hence why $product['qty'] didn't exist.