如何有效地將資料從多個複選框和文字方塊數組插入 MySQL 資料庫，同時處理未選取的複選框並防止資料操作？

<form method="POST">

<input type="hidden" name="item[]" value="cupcake">
<input type="text" name="items" value="cupcake" readonly><br>
<b>Price :</b> <span name="price" value="3.00">.00</span><br>
Quantity: <input tabindex="1" name="quantity[]" min="0" max="5" type="number" class="quantity" value="1" /><br>
<input tabindex="1" name="checkbox[0]" type="checkbox" value="17" /><span>Add to Cart</span></label></div></div></td><br>

<input type="hidden" name="item[]" value="cake">
<input type="text" name="items" value="cake" readonly><br>
<b>Price :</b> <span name="price" value="20.00">.00</span><br>
Quantity: <input tabindex="1" name="quantity[]" min="0" max="5" type="number" class="quantity" value="1" /><br>
<input tabindex="1" name="checkbox[1]" type="checkbox" value="20" /><span>Add to Cart</span></label></div></div></td><br>

<input type="submit" name = "insertBT"><br>
</form>

if(isset($_POST['insertBT'])) {
    $conn = new mysqli ($servername, $username, $password, $db);
    if($conn->connect_error) {
        die ("Connection Failed : " . $conn->connect_error);
    } else {
        $stmt = $conn->prepare("INSERT INTO purchases (Product, Quantity, Price) VALUES (?, ?, ?)");
        $stmt->bind_param("sis", $name, $quantity, $price);
        foreach ($_POST['checkbox'] as $i => $price) {
            $name = $_POST['name'][$i];
            $quantity = $_POST['quantity'][$i];
            $stmt->execute();
        }
    }
}