mysql 套事物实例

public static DataSet GetPPriceList(string aircompany, string departPort, string arrivePort, string cabin,Boolean flag=false)
        {
            string sql = "SELECT ID, AirCompany,DepartCode,ArriveCode,ServerGrade,Cabin,Price,Agio,SaleBeginTime,SaleEndTime,TravelBeginTime,TravelEndTime FROM PPrice WHERE `Status`=1 AND SaleEndTime>NOW() AND TravelEndTime>NOW()  ";
            if (aircompany != "")
            {
                sql += " and AirCompany='" + aircompany + "' ";
            }
            if (departPort != "")
            {
                sql += " and DepartCode='" + departPort + "' ";
            }
            if (arrivePort != "")
            {
                sql += " and ArriveCode='" + arrivePort + "' ";
            }
            if (cabin != "")
            {
                sql += " and Cabin='" + cabin + "'";
            }
            sql += " ORDER BY ModifyTime DESC ";
            DataSet ds = null;
            using (MySql.Data.MySqlClient.MySqlConnection conn = new MySql.Data.MySqlClient.MySqlConnection(MySqlHelper.ConnectionString))
            {
                if (ConnectionState.Open != conn.State)
                    conn.Open();
                if (flag)
                {
                    MySql.Data.MySqlClient.MySqlTransaction tra = conn.BeginTransaction(IsolationLevel.ReadUncommitted);
                    ds = MySqlHelper.ExecuteDataset(tra, CommandType.Text, sql);
                    tra.Commit();
                }
                else
                {
                    ds = MySqlHelper.ExecuteDataset(conn, CommandType.Text, sql);
                }
            }
            return ds;
        }