c# 连接数据库

 using System;
using System.Data;
using System.Data.SqlClient;

namespace DataReader1App
{
 /// <summary>
 /// Class1 的摘要说明。
 /// </summary>
 class DataReader1
 {
  /// <summary>
  /// 应用程序的主入口点。
  /// </summary>
  [STAThread]
  static void Main(string[] args)
  {
   SqlConnection connection = new SqlConnection(@"Data Source=(local);Integrated Security=SSPI;"+
    "Initial Catalog = NorthWind");

   connection.Open();

   SqlCommand command = connection.CreateCommand();

   command.CommandText = "SELECT EmployeeID, FirstName,LastName from Employees";

   SqlDataReader reader = command.ExecuteReader();

   while(reader.Read())
   {
    Console.WriteLine("/t{0}/t{1}/t{2}",reader["EmployeeID"],reader["FirstName"],reader["LastName"]);

   }

   reader.Close();
   connection.Close();
  }
 }
}