C# 连接 sql server

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;

namespace ConsoleApplication4
{
    class Program
    {

        static void Main(string[] args)
        {
            try
            {
                //sqlserver身份验证
                string sqlconn = "server=127.0.0.1;database=dingyingsi;uid=sa;pwd=Dys123456;";
                //windows身份验证
                //string sqlconn = "server=(local);database=keede1228;integrated security=SSPI;";
                string select = "select id, username, password from [user]";
                SqlConnection conn = new SqlConnection(sqlconn);
                Console.WriteLine("");
                conn.Open();
                Console.WriteLine("");
                SqlCommand cmd = new SqlCommand(select, conn);
                SqlDataReader reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                    Console.WriteLine("id:{0} username:{1} password:{2}", reader[], reader[], reader[]);
                }
                conn.Close();
                Console.WriteLine("");
                Console.ReadKey();
            }catch(Exception e){
                Console.WriteLine(e.Message);
                Console.ReadKey();
            }
        }
    }
}