[原]DataReader 处理多个结果集—NextResult的用法

仔细查看您的数据库代码，看是否存在多次进入数据库的请求路径。每个这样的往返都会降低应用程序可以提供的每秒请求数量。通过在一个数据库请求中返回多个结果集，可以节省与数据库进行通信所需的总时间长度。同时因为减少了数据库服务器管理请求的工作，还会使得系统伸缩性更强。
简单示例如下：

一、返回多个数据集的存储过程
CREATE PROC Proc ---Multiple Resultsets
AS
SELECT * FROM Users
SELECT * FROM Users WHERE State = 'CA'
GO

二、取多个数据集的代码
   String ConnString  = "User ID=sa;password=sa;Initial Catalog=pubs;Data Source=myServer";
   SqlConnection Connection = new SqlConnection(myConnString);
   SqlCommand Command = new SqlCommand();
   SqlDataReader reader ;

   Command.CommandType = CommandType.StoredProcedure;
   Command.Connection = Connection;
   Command.CommandText = "Proc";
   int RecordCount=0;
   try
   {
    Connection.Open();
    reader = command.ExecuteReader();
    int RecordCount=0;

    // read the data from that resultset
    while (reader.Read())
    {
     RecordCount = RecordCount + 1;
    }
    Response.Write("Total number of Users:" + RecordCount.ToString());

    // read the next resultset
    reader.NextResult();
    RecordCount = 0;

    // read the data from that second resultset
    while (reader.Read())
    {
     RecordCount = RecordCount + 1;
    }
    Response.Write("Total number of Users from California:" + RecordCount.ToString());
   }
   catch (Exception ex)
   {
    MessageBox.Show(ex.ToString());
   }
   finally
   {
    Connection.Close();
   }