public function buy(Order $order) { $query = "INSERT INTO cartsproducts (cartId, productId, quantity)\n VALUES (?, ?, ?)"; $params = [$order->getCartId(), $order->getProductId(), $order->getQuantity()]; $this->db->query($query, $params); $result = $this->db->row(); $query = "UPDATE carts SET value = value + ?\n WHERE carts.id = ?"; $params = [$order->getQuantity() * $order->getPrice(), $order->getCartId()]; $this->db->query($query, $params); $query = "UPDATE products SET quantity = quantity - ?\n WHERE products.id = ?"; $params = [$order->getQuantity(), $order->getProductId()]; $this->db->query($query, $params); return $result; }