Trying To Loop Through Two $_POST arrays without success

Question

The following is my form where I have two different $_POST arrays, "ids" and "quantities". I'm trying to loop through them so I can update a database column.

My form:

<form action="" method="post">
            <ul>
<?php       foreach($rows as $row) { ?>
                <li>
                    <input type="hidden" name="ids[]" value="<?php echo $row['id']; ?>">
                </li>
                <li>
                    <input type="text" name="quantities[]" value="1" size="3">
                    <?php echo $row['title']; ?>
                </li>   
<?php       } ?>
                <li>
                    <br><input type="submit" value="Submit New Release Edits" name="submit">
                </li>
            </ul>
            </form>

The code I am attempting to run in order to update the database properly is:

if(isset($_POST['submit'])) {
        foreach($_POST['quantities'] as $quantity) {
            foreach($_POST['ids'] as $id) {
                $stmt = $db->prepare("UPDATE titles SET release_quant=:release_quant WHERE id=:id");
                $stmt->bindValue(':release_quant', $quantity, PDO::PARAM_INT);
                $stmt->bindValue(':id', $id, PDO::PARAM_INT);
                $stmt->execute();
            }
        }
    }

I know the code isn't correct, because it doesn't loop through the quantity and id arrays at the same time. How do I need to adjust my code?

Answer 1

Try this: (replaced the second loop by direct access, so you only get the ID wanted)

$i = 0;
if(isset($_POST['submit'])) {
        foreach($_POST['quantities'] as $quantity) {
                $id = $_POST['ids'][$i];
                $stmt = $db->prepare("UPDATE titles SET release_quant=:release_quant WHERE id=:id");
                $stmt->bindValue(':release_quant', $quantity, PDO::PARAM_INT);
                $stmt->bindValue(':id', $id, PDO::PARAM_INT);
                $stmt->execute();
                $i++;
        }
    }