laravel防止重复记录

Question

如何正确检查数据库中是否已存在数据并将消息返回到视图中$check = PropertyReservation::where('res_id', Auth::user()->res_id)->where('property_no',$reservation->property_no)->first();        if($check){            return redirect('/reservations')->with('success','You have an existing reservation for this item ' );        }        else{            $reservation->reservation_name = $resident->resident_fname;            $reservation->reservation_type = $request->input('reservation_type');            $reservation->reservation_quantity = $request->input('reservation_quantity');            $reservation->save();        }        return redirect('/reservations');