“我想在Laravel中执行基本的CRUD操作，我想根据product_id检索存储在数据库中的数据，并执行更新和删除相关数据等操作。但是，当我编写搜索查询时，如$cartItem = CartItem：：where（'product_id'，$productId）->where（'order_code'，$orderCode）->first（）;，即使数据库中存在数据，它也会返回空。
class Store extends Controller {

public function __invoke($id)
{
   try
   {
     $products = Products::findOrFail($id);
     $quantity = rand(1,10);
     if(!$products)
       {
          throw new \Exception("product not found");
          
          
        }
        $orderCode = session('order_code');
        if(!$orderCode)
           {
             $orderCode = rand(100,2000);
             session(['order_code' => $orderCode]);
            }
        $cartItem = CartItem::where('product_id', $productId)->where('order_code', $orderCode)>first();
            if ($cartItem) 
            {
                $cartItem->quantity+=$quantity;
                $cartItem->total_price = $cartItem->unit_price * $cartItem->quantity;
                $cartItem->save();
                throw new \Exception('The product is available in the cart');
            }
       
            $cart_item = new CartItem([
               "title"=>$products->title,
                'quantity'=>$quantity,
                'unit_price'=> $products->price,
                'total_price'=>$products->price*$quantity,
                'order_code' => $orderCode,
                "product_id"=>$products->product_id,
            ]);
            $cartSave = $cart_item->save();
            if($cartSave){
                throw new \Exception('product added to cart');
            }
    
    } 
    catch(\Exception $e)
    {
        \Log::debug($e->getMessage());
        return Response::error($e->getMessage());
    }
}

} 你的文字