High Quality - Addcartphp Num

Let's assume you're adding a product with a unique id, name, price, and a num (quantity) you want to add.

function addToCart($id, $name, $price, $num) 
    // Assuming $_SESSION['cart'] is already set up
// Check if item is already in cart
    foreach ($_SESSION['cart'] as &$item) 
        if ($item['id'] == $id) 
            $item['num'] += $num;
            return;
// If item is not in cart, add it
    $_SESSION['cart'][] = array(
        'id' => $id,
        'name' => $name,
        'price' => $price,
        'num' => $num
    );
// Example usage
addToCart(1, "Sample Product", 19.99, 2);

To support addcartphp num high quality, you need a normalized database structure.

-- Products table
CREATE TABLE `products` (
  `id` INT(11) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
  `sku` VARCHAR(50) NOT NULL,
  `name` VARCHAR(255) NOT NULL,
  `price` DECIMAL(10,2) NOT NULL,
  `stock_quantity` INT(11) NOT NULL DEFAULT 0,
  `status` TINYINT(1) DEFAULT 1,
  INDEX `idx_stock` (`stock_quantity`, `status`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
-- Optional: Persistent carts (for logged-in users)
CREATE TABLE user_carts (
id INT(11) UNSIGNED AUTO_INCREMENT PRIMARY KEY,
user_id INT(11) UNSIGNED NOT NULL,
product_id INT(11) UNSIGNED NOT NULL,
quantity INT(11) UNSIGNED NOT NULL,
added_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
UNIQUE KEY unique_user_product (user_id, product_id)
) ENGINE=InnoDB;
 addcartphp num high quality

session_start();
require_once 'db.php';
require_once 'csrf.php';
if ($_SERVER['REQUEST_METHOD'] === 'POST' && verifyCsrfToken($_POST['token'])) 
$productId = filter_input(INPUT_POST, 'id', FILTER_VALIDATE_INT);
$quantity = filter_input(INPUT_POST, 'num', FILTER_VALIDATE_INT, ['options' => ['min_range' => 1]]); Let's assume you're adding a product with a
if (!$productId 

// After login check
if ($num > 0 && $num <= $product['stock_quantity']) 
    $stmt = $pdo->prepare("
        INSERT INTO cart_items (user_id, product_id, quantity) 
        VALUES (?, ?, ?)
        ON DUPLICATE KEY UPDATE quantity = quantity + ?
    ");
    $stmt->execute([$_SESSION['user_id'], $product_id, $num, $num]);
// Validate final quantity does not exceed stock
$check = $pdo->prepare("
    SELECT ci.quantity, p.stock_quantity 
    FROM cart_items ci 
    JOIN products p ON ci.product_id = p.id
    WHERE ci.user_id = ? AND ci.product_id = ?
");
$check->execute([$_SESSION['user_id'], $product_id]);
$row = $check->fetch();
if ($row['quantity'] > $row['stock_quantity']) 
    // Rollback
    $pdo->prepare("UPDATE cart_items SET quantity = ? WHERE user_id = ? AND product_id = ?")
        ->execute([$row['stock_quantity'], $_SESSION['user_id'], $product_id]);
    die(json_encode(['error' => 'Adjusted to max stock']));