using system;
using system.configuration;
using system.data.sqlclient;
using system.data;
using system.collections;
比如：
// 打開數據庫

轉自：動態網制作指南 www.knowsky.com
public static sqlconnection openconnection()
  {
   sqlconnection mysqlconn = new sqlconnection(configurationsettings.appsettings["connstring"]);
  

   try
   {
    mysqlconn.open();
   }
   catch (exception e)
   {
    //rethrow this exception
    throw e;
   }

   return mysqlconn;
  }

// 執行sql返回dataset
public static dataset getdataset(string sqlquery)
  {
   sqlconnection cn = dbobject.openconnection();
   sqldataadapter da = new sqldataadapter(sqlquery, cn);
   dataset ds = new dataset();
  
   da.fill(ds);
  
   //release resources
   da.dispose();
   da = null;
   cn.close();
   cn = null;

   return ds;
  }

// 執行sql語句
public static void executeupdatequery(string sqlquery)
  {
   sqlconnection cn = dbobject.openconnection();
   sqlcommand cmd = new sqlcommand();

   cmd.commandtext = sqlquery;
   cmd.commandtype = commandtype.text;
   cmd.connection = cn;
   cmd.executenonquery();
  
   cn.close();
   cn = null;
  }