对PHP写库存管理系统中的订单跟踪功能进行代码生成

CREATE TABLE `orders` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `order_number` varchar(50) NOT NULL,
  `status` enum('pending','processing','shipped','delivered','cancelled') NOT NULL,
  `created_at` datetime NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

class OrderTracking {
  private $db;

  public function __construct($db) {
    $this->db = $db;
  }

  // 创建新订单
  public function createOrder($orderNumber) {
    $status = 'pending';
    $createdAt = date('Y-m-d H:i:s', time());

    $sql = "INSERT INTO orders (order_number, status, created_at)
            VALUES ('$orderNumber', '$status', '$createdAt')";
    $this->db->query($sql);

    return $this->db->insert_id;
  }

  // 更新订单状态
  public function updateOrderStatus($orderId, $status) {
    $sql = "UPDATE orders
            SET status = '$status'
            WHERE id = $orderId";
    $this->db->query($sql);
  }

  // 获取订单状态
  public function getOrderStatus($orderId) {
    $sql = "SELECT status FROM orders WHERE id = $orderId";
    $result = $this->db->query($sql);
    $row = $result->fetch_assoc();

    return $row['status'];
  }
}

// 假设我们已经建立了数据库连接对象$db
$orderTracking = new OrderTracking($db);

// 创建新订单
$orderNumber = 'ORD-20210101-001';
$orderId = $orderTracking->createOrder($orderNumber);

// 更新订单状态
$orderTracking->updateOrderStatus($orderId, 'processing');

// 获取订单状态
$status = $orderTracking->getOrderStatus($orderId);
echo '订单状态：' . $status;