GameFramework.DataDML.LoadSingleTableActivationCode C# (CSharp) Method

        private static GeneralRecordData LoadSingleTableActivationCode(List<string> primaryKeys)
        {
            GeneralRecordData ret = null;
            try {
              using (MySqlCommand cmd = new MySqlCommand()) {
                cmd.Connection = DBConn.MySqlConn;
                cmd.CommandType = CommandType.StoredProcedure;
                cmd.CommandText = "LoadSingleTableActivationCode";
                if(primaryKeys.Count != 1)
                    throw new Exception("primary key number don't match !!!");
                MySqlParameter inputParam;
                inputParam = new MySqlParameter("@_ActivationCode", MySqlDbType.VarChar);
                inputParam.Direction = ParameterDirection.Input;
                inputParam.Value = primaryKeys[0];
                inputParam.Size = 32;
                cmd.Parameters.Add(inputParam);
                using (DbDataReader reader = cmd.ExecuteReader()) {
                  if (reader.Read()) {
                    ret = new GeneralRecordData();
                    object val;
                    TableActivationCode msg = new TableActivationCode();
                    val = reader["ActivationCode"];
                    msg.ActivationCode = (string)val;
                    ret.PrimaryKeys.Add(val.ToString());
                    val = reader["IsActivated"];
                    msg.IsActivated = (bool)val;
                    val = reader["AccountId"];
                    msg.AccountId = (string)val;
                    ret.DataVersion = (int)reader["DataVersion"];
                    ret.Data = DbDataSerializer.Encode(msg);
                  }
                }
              }
            } catch (Exception ex) {
              DBConn.Close();
              throw ex;
            }
            return ret;
        }