与数据库交互的提交输入类型

Question

how can I with a input type submit can increment something or decrement something in a database?

In my case I'm doing an inventory managment tool and in a html table I have a input type that adds stock and other that removes, how can I connect those buttons with the database?

Answer 1

In the form, use two inputs with the same name but different values.

<input type="submit" name="direction" value="+">
<input type="submit" name="direction" value="-">

Then in the PHP, check the value of $_POST['direction'] and use that in the database update.

if ($_POST['direction'] == '+') {
    $increment = 1;
} elseif ($_POST['direction'] == '-') {
    $increment = -1;
} else {
    die("Invalid direction");
}
$stmt = $conn->prepare("UPDATE yourTable SET something = something + ? WHERE id = ?")
$stmt->bind_param("ii", $increment, $id);
$stmt->execute();