using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Data;//自己添加

using System.Data.SqlClient;//微软为SQL设计

 

namespace 操作数据库练习

{

    class Program

    {

        static void Main(string[] args)

        {

            string connectionString = "server=.;database=Test;integrated security=true";

            //SqlConnection connection = new SqlConnection(connectionString);

            //connection.Open();

            //Console.WriteLine(connection.State);

            //connection.Close();

            ////实际上的close里面调用了dispose

            //Console.WriteLine(connection.State);

            //Console.ReadKey();

            SqlConnection connection;

            //using第二个作用：创建对象

            //在using这个代码块结束以后，自动调用该对象的.close()方法

            using (connection = new SqlConnection(connectionString))

            {

                connection.Open();

                Console.WriteLine(connection.State);

            }

            //using（）本质

            //1.创建对象

            //2.try...

            //3.finall{.Dispose();}

            Console.WriteLine(connection.State);

        }

    }

}