Почему не обновляется процедура?

declare @cityName nvarchar(30)
SET @cityName = N'Сиде'
DECLARE @CityID int
set @CityID = (SELECT Cities.Id FROM dbo.Cities WHERE Cities.Name = @cityName)
select @CityID

declare @cityName nvarchar(30)
SET @cityName = 'Сиде'
DECLARE @CityID int
set @CityID = (SELECT Cities.Id FROM dbo.Cities WHERE Cities.Name = @cityName)
select @CityID

set @CityID = (SELECT Cities.Id FROM dbo.Cities WHERE Cities.Name = N(@cityName))

'N' is not a recognized built-in function name.

public static void AddHotel(string cityName, string adress, int rating, int? line, string name, int? distanceToBeach, int? @distaceToAirport)
        {
            using (SqlConnection connection = new SqlConnection(ConnectionString))
            {
                string sql = "[dbo].[AddHotel]";

                using (SqlCommand command = new SqlCommand(sql, connection))
                {
                    command.CommandType = CommandType.StoredProcedure;

                    command.Parameters.Add("@adress", SqlDbType.NVarChar, 60);
                    command.Parameters["@adress"].Value = adress;
                    command.Parameters.Add("@rating", SqlDbType.Int);
                    command.Parameters["@rating"].Value = rating;
                    command.Parameters.Add("@line", SqlDbType.Int);
                    command.Parameters["@line"].Value = rating;
                    command.Parameters.Add("@name", SqlDbType.NVarChar, 60);
                    command.Parameters["@name"].Value = name;
                    command.Parameters.Add("@distanceToBeach", SqlDbType.Int);
                    command.Parameters["@distanceToBeach"].Value = distanceToBeach;
                    command.Parameters.Add("@distanceToAirport", SqlDbType.Int);
                    command.Parameters["@distanceToAirport"].Value = distaceToAirport;
                    command.Parameters.Add("@cityName", SqlDbType.NVarChar, 30);
                    command.Parameters["@cityName"].Value = cityName;
                    connection.Open();
                    command.ExecuteNonQuery();
                    connection.Close();
                }
            }

В INSERT [Hotels] нет поля кода города.

INSERT INTO [dbo].[Hotels]
           ([Name], [City],[Address],[Rating], [DistanceToBeach], [DistanceToAirport], [Line], [Discription])
     VALUES
           (@name,@CityID,@adress, @rating, @distanceToBeach, @distanceToAirport, @line, 'some discr')

Дополнение. Поскольку вы передаёте город не кодом, а названием, нужно обрабатывать его отсутствие в базе: