oracle获取clob调优

引用Oracle.DataAccess.dll，，在oracle 安装目录下的D:\oracle\product\10.2.0\db_1\ODP.NET\bin\1.x\Oracle.DataAccess.dll

 public static void GetFirstData(string connectionString, string commandString,out string xml,out string last_update_dtime,
             params OracleParameter[] parameters)
        {
            using (Oracle.DataAccess.Client.OracleConnection myConnection = new Oracle.DataAccess.Client.OracleConnection(connectionString))
            {
                try
                {
                    xml = "";
                    last_update_dtime = "";
                    Oracle.DataAccess.Client.OracleCommand myORACCommand = myConnection.CreateCommand();

                    myORACCommand.CommandText = commandString;

                    myConnection.Open();

                    Oracle.DataAccess.Client.OracleDataReader myDataReader = myORACCommand.ExecuteReader();
                    myDataReader.Read();
                    xml = myDataReader.GetValue(1).ToString();
                    last_update_dtime = myDataReader.GetValue(0).ToString();
                    myDataReader.Close();
                    myConnection.Close();

                }
                catch (Exception ex)
                {
                    xml = "";
                    last_update_dtime = "";
                }
            };

        }