public void InsertRoom(Room room)
        {
            SqlConnection connection = null;

            try
            {
                connection = retrieveConnection();

                SqlCommand command = new SqlCommand("insert into room values (@Room, @Zipcode)", connection);
                command.Parameters.Add(new SqlParameter("Room", room.RoomKey));
                command.Parameters.Add(new SqlParameter("Zipcode", room.Zipcode));

                command.ExecuteNonQuery();
            }
            finally
            {
                connection.Close();
            }
        }
        public Room QueryRoom(string roomKey)
        {
            SqlConnection connection = null;
            SqlDataReader reader = null;
            Room room = null;

            try
            {
                connection = retrieveConnection();

                SqlCommand command = new SqlCommand("select Room, Zipcode from room where Room = @roomKey", connection);
                command.Parameters.Add(new SqlParameter("roomKey", roomKey));

                reader = command.ExecuteReader();

                if (reader.Read())
                {
                    room = new Room();
                    room.RoomKey = reader["Room"].ToString();
                    room.Zipcode = reader["Zipcode"].ToString();
                }
                else
                    throw new Exception("Room not found!");

                return room;
            }
            finally
            {
                reader.Close();
                connection.Close();
            }
        }
        public void UpdateRoom(Room room, string roomKey)
        {
            SqlConnection connection = null;

            try
            {
                connection = retrieveConnection();

                SqlCommand command = new SqlCommand("update room set Room = @Room, Zipcode = @Zipcode where Room = @roomKey", connection);
                command.Parameters.Add(new SqlParameter("Room", room.RoomKey));
                command.Parameters.Add(new SqlParameter("Zipcode", room.Zipcode));
                command.Parameters.Add(new SqlParameter("roomKey", roomKey));

                command.ExecuteNonQuery();
            }
            finally
            {
                connection.Close();
            }
        }