public Boolean InsertDataIntoDB()
        {
            DBManager dbManager = new DBManager();
            MySqlConnection con = null;

            try
            {
                String ip = Config.DB_SERVER_IP;
                con = dbManager.CreateConnection(ip, Config.DATABASE_CORREL);
                con.Open();

                foreach (Tuple<DateTime, double> row in _data)
                {
                    InsertDataIntoDB_Raw(con, row);
                }
                return true;
            }
            catch (System.Exception e)
            {
                logger.Error(e.ToString());
            }
            finally
            {
                dbManager.Close(con);
            }
            return false;
        }
        public Boolean DeletePrevDataInDB()
        {
            DBManager dbManager = new DBManager();
            MySqlConnection con = null;

            try
            {
                String ip = Config.DB_SERVER_IP;
                con = dbManager.CreateConnection(ip, Config.DATABASE_CORREL);
                con.Open();

                String query = String.Format("delete from raw_price_data where Ticker = '{0}'", kStockPerFinanceAsset);
                MySqlCommand cmd = new MySqlCommand(query, con);
                int ret = cmd.ExecuteNonQuery();
                if (ret < 0)
                {
                    throw new Exception();
                }

                return true;
            }
            catch (System.Exception e)
            {
                logger.Error(e.ToString());
            }
            finally
            {
                dbManager.Close(con);
            }
            return false;
        }