ADO.NET中的sql连接

using System.Data;            // Use ADO.NET namespace

using System.Data.SqlClient;  

 SqlConnection thisConnection = new SqlConnection(

            @"Data Source=GY; Initial Catalog=northwind;uid=sa;password=datadog"); //先建立连接

 thisConnection.Open();//打开连接

         SqlCommand thisCommand = thisConnection.CreateCommand();//直接指定conn的command

也可以这样        //  SqlCommand cmd = new SqlCommand();

       //  cmd.Connection = thisConnection;

cmmand的sql命令         

thisCommand.CommandText = "SELECT CustomerID, CompanyName from Customer";

         SqlDataReader thisReader = thisCommand.ExecuteReader();//sqldatareader不可以用new 必须直接与command关联

//用reader读出表

         while (thisReader.Read())

         {

            // Output ID and name columns

            Console.WriteLine("/t{0}/t{1}", 

               thisReader["CustomerID"], thisReader["CompanyName"]);

         // Close reader 用完要关闭

         thisReader.Close();

         // Close connection

         thisConnection.Close ()