关于数据的导入问题

class Program  
   {  
       static volatile bool result;  
       static void Main(string[] args)  
       {  
          DataSet ds = ExportDataSet();  
 
          //使用2个线程模拟并发操作  
          Thread t = new Thread(delegate() { result = Insert(ds); Console.WriteLine(result ? "导入成功" : "导入失败"); });  
          t.Start();  
          Thread t1 = new Thread(delegate() { result = Insert(ds); Console.WriteLine(result ? "导入成功" : "导入失败"); });  
          t1.Start();  
          Console.ReadLine();  
       }  
 
       /// <summary>  
       /// 获取数据DataSet  
       /// </summary>  
       /// <returns></returns>  
 
       static private DataSet ExportDataSet()  
       {  
 
           //局域网的某服务器模拟数据库远程连接  
           sqlConnection RemoteConn = new sqlConnection("Data Source=192.168.0.183;Initial Catalog=northwind;User ID=sa;Password=sa");  
 
 
 
           using (  
 
            /*目标表与源表结构并不相同，目标表只包含OrderID、CustomerID、EmployeeID、ShipCountry这四个字段。注意这里字段是区分大小写的，不然sqlBulkcopy的WritetoServer方法会报运行时异常：“给定的 ColumnMapping 与源或目标中的任意列均不匹配”的处理方法。这个地方浪费了我1个小时才发现*/ 
            sqlDataAdapter oda = new sqlDataAdapter("SELECT [OrderID],[CustomerID],[EmployeeID],[ShipCountry] FROM [northwind].[dbo].[Orders]",RemoteConn))  
 
           //如果目标表与源表结构完全一致，则用下面语句即可，msdn的例子也只是这样  
 
            //sqlDataAdapter oda = new sqlDataAdapter("SELECT * FROM [ednoland].[dbo].[score]",RemoteConn))  
           {  
               DataSet ds = new DataSet();  
 
               oda.Fill(ds,"Orders");//给定表名  
 
                 return ds;  
 
           }  
 
       }  
 
       /// <summary>  
       /// 将DataSet导入远程数据库(未来放在WebService中)  
       /// </summary>  
       /// <param name="ds"></param>  
       /// <returns></returns>  
       public static bool Insert(DataSet ds)  
       {  
 
 
           using (sqlConnection sqlconn = new sqlConnection("Data Source=.;Initial Catalog=northwind;User ID=sa;Password=sa"))  
           {  
               sqlconn.open();  
               sqlTransaction sqlbulkTransaction = sqlconn.BeginTransaction(IsolationLevel.ReadCommitted);  
 
 
 
               using (sqlBulkcopy sbc = new sqlBulkcopy(sqlconn,sqlBulkcopyOptions.KeepIdentity,sqlbulkTransaction))  
               {  
                   sbc.BatchSize = 20000;//20000行每连接  
                   sbc.BulkcopyTimeout = 50;//50秒超时  
                   if (ds.Tables == null || ds.Tables.Count == 0)  
                       return false;  
 
                   if (ds.Tables.Count == 1)  
                   {  
 
 
                       return BulkInsert(sbc,ds.Tables[0],sqlbulkTransaction); ;  
 
                   }  
                   else 
                   {  
                       bool res = true;  
                       foreach (DataTable dt in ds.Tables)  
                       {  
 
                           res = BulkInsert(sbc,dt,sqlbulkTransaction);  
 
                       }  
                       return res;  
                   }  
 
               }  
           }  
 
       }  
 
       private static bool BulkInsert(sqlBulkcopy sbc,DataTable dt,sqlTransaction sqlbulkTransaction)  
       {  
          
           bool res = true;  
                      try 
           {  
 
             //将DataTable表名作为待导入库中的目标表名  
               sbc.DestinationTableName = dt.TableName;  
 
 
 
              //将数据集合和目标服务器库表中的字段对应  
               for (int i = 0; i < dt.Columns.Count; i++)  
               {  
                   //sbc.columnmappings.Add(dt.Columns[i].ColumnName,dt.Columns[i].ColumnName);  
                     sbc.columnmappings.Add(i,i);//可以避免字段大小写不一致造成无法映射的问题  
               }  
 
               sbc.WritetoServer(dt);  
 
               //提交事务  
               sqlbulkTransaction.Commit();  
               res = true;  
           }  
           catch (sqlException ex)  
           {  
               res = false;  
               sqlbulkTransaction.Rollback();  
           }  
 
           return res;          }      }