Updating DB from grid array - php

Question

I am using DHTMLX javascript library to present a grid in a form. My users could have hundreds of products in their grid but I am only capturing the the rows they add a price to. I then need to add those rows to a MySQL database along with some other information.
Getting standard $POST information and manipulating it in my PHP scripts is about the limit of my skills so far so where I need help is the array created by the updated rows. An example of what is being captured in my $POST is:
Array
(
[product] => 64
[dept] => 000
[submit] => Submit
[gridbox_1_4] => 422
[gridbox_64_4] => 534
[gridbox_175_4] => 1234
[gridbox_180_4] => 645
)
I currently capture the basic $POST variables with:
$itemcat = filter($_POST['product']);
$dept7 = filter($_POST['dept']);
My question is how do I capture the gridbox variables so I can use them in an INSERT statement? The only number that will change is the middle number which represents a primary key in my database for the products I need to INSERT into another table. I am assuming I need to explode the $POST variable somehow maybe? Then how do I INSERT them using something like:
"INSERT INTO submissions
(product_id, user_id,submission_id, sugg_price)
VALUES ('" . $gridbox_id . "','" . $myid . "','NULL', '" . $sugg . "')";
All of my reading today on arrays has given me a good understanding of how they work from a 100ft view but not how to specifically solve my problem or even how to start. I'm hoping the community can send me down the right path.

Answer 1

You can loop over the $_POST array and perform a regular expression match on each key:
// PDO will make your life so much easier
$dbh = new PDO('mysql:dbname=testdb;host=127.0.0.1', $user, $password);
// prepared statements are great - prepare once, use many
$stmt = $dbh->prepare('
INSERT INTO submissions
( product_id, user_id, submission_id, sugg_price)
VALUES
(:product_id, :user_id, NULL , :sugg_price)
');
// avoid SQL injection by passing your variables in as parameters
// see http://bobby-tables.com to understand why
$stmt->bindValue('user_id', $myid);
foreach ($_POST as $key => $val) {
if (preg_match("/^gridbox_(\d+)_4$/", $key, $matches)) {
$stmt->execute(array(
':product_id' => $matches[1],
':sugg_price' => $val
));
}
}