using System.Data;

            using System.Data.OleDb;

            ..
            
string strConnection="Provider=Microsoft.Jet.OleDb.4.0;";
mailto:strConnection+=@%22Data Source=C:BegASPNETNorthwind.mdb";
            
OleDbConnection objConnection=new OleDbConnection(strConnection);

            ..
            
objConnection.Open();

            objConnection.Close();
            

            
strConnection+="Data Source=";

            strConnection+=MapPath("Northwind.mdb");
            

            
using System.Data;

            using System.Data.SqlClient;

            ..
            
string strConnection="user id=sa;password=;";

            strConnection+="initial catalog=Northwind;Server=YourSQLServer;";

            strConnection+="Connect Timeout=30";
            
SqlConnection objConnection=new SqlConnection(strConnection);

            ..
            
objConnection.Open();

            objConnection.Close();
            

            
using System.Data.OracleClient;

            using System.Data;
            
//在窗体上添加一个按钮，叫Button1，双击Button1，输入以下代码
            
private void Button1_Click(object sender, System.EventArgs e)

            {

            string ConnectionString="Data Source=sky;user=system;password=manager;";//写连接串

            OracleConnection conn=new OracleConnection(ConnectionString);//创建一个新连接

            try

            {conn.Open();

            OracleCommand cmd=conn.CreateCommand();

            cmd.CommandText="select * from MyTable";//在这儿写sql语句

            OracleDataReader odr=cmd.ExecuteReader();//创建一个OracleDateReader对象

            while(odr.Read())//读取数据，如果odr.Read()返回为false的话，就说明到记录集的尾部了           
            
{

            Response.Write(odr.GetOracleString(1).ToString());//输出字段1，这个数是字段索引，具体怎么使
            
用字段名还有待研究

            }

            odr.Close();

            }

            catch(Exception ee)

            {

            Response.Write(ee.Message); //如果有错误，输出错误信息

            }

            finally

            {

            conn.Close(); //关闭连接

            }

            }
            

            
using MySQLDriverCS; 
            
// 建立数据库连接

            MySQLConnection DBConn;

            DBConn = new MySQLConnection(new MySQLConnectionString
            
("localhost","mysql","root","",3306).AsString);

            DBConn.Open(); 
            
// 执行查询语句

            MySQLCommand DBComm;

            DBComm = new MySQLCommand("select Host,User from user",DBConn); 
            
// 读取数据

            MySQLDataReader DBReader = DBComm.ExecuteReaderEx(); 
            
// 显示数据

            try

            {

            while (DBReader.Read())

            {

            Console.WriteLine("Host = {0} and User = {1}", 
            
DBReader.GetString(0),DBReader.GetString(1));

            }

            }

            finally

            {

            DBReader.Close();

            DBConn.Close();

            } 
            
//关闭数据库连接

            DBConn.Close();
            

            
OleDbConnection1.Open();

            //打开数据库连接

            OleDbDataAdapter1.Fill(dataSet1,"Address");

            //将得来的数据填入dataSet

            DataGrid1.DataBind();

            //绑定数据

            OleDbConnection1.Close();

            //关闭连接 
            
//增加数据库数据

            在Web Form上新增对应字段数量个数的TextBox，及一个button，为该按键增加Click响应事件代码如下：
            
this.OleDbInsertCommand1.CommandText = "INSERTsintosADDRESS(NAME,

            EMAIL, AGE, ADDRESS) VALUES

            ('"+TextBox1.Text+"','"+TextBox2.Text+"','"+TextBox3.Text+"','"+TextBox4.Text+"')";

            OleDbInsertCommand1.Connection.Open();

            //打开连接

            OleDbInsertCommand1.ExecuteNonQuery();

            //执行该SQL语句

            OleDbInsertCommand1.Connection.Close();

            //关闭连接 
            

            
Provider=Sybase.ASEOLEDBProvider.2;

            Initial Catalog=数据库名;

            User ID=用户名;Data Source=数据源;

            Extended Properties="";

            Server Name=ip地址;

            Network Protocol=Winsock;

            Server Port Address=5000;