Tárolt eljárás C# kód

public bool CheckRendszam(string rendszam)
        {
            OracleConnection conn = getConnection();
            conn.Open();

            OracleCommand command = new OracleCommand()
            {
                CommandType = System.Data.CommandType.StoredProcedure,
                CommandText = "sf_check_rendszam",
                Connection = conn
            };

            OracleParameter returnValue = (new OracleParameter("returnValue", OracleDbType.Varchar2, 5));
            returnValue.Direction = ParameterDirection.ReturnValue;
            command.Parameters.Add(returnValue);


            OracleParameter rendszamParameter = new OracleParameter()
            {
                ParameterName = "p_rendszam",
                Direction = System.Data.ParameterDirection.Input,
                DbType = System.Data.DbType.String,
                Value = rendszam

            };
            command.Parameters.Add(rendszamParameter);


            command.ExecuteNonQuery();
            conn.Close();
            return Boolean.Parse(command.Parameters["returnValue"].Value.ToString());
        }