增删改 语句：

SqlConnection conn = new SqlConnection("server=.;database=mydb;uid=sa;pwd=123"); conn.Open(); //SqlCommand cmd = new SqlCommand(); //构造命令对象 //cmd.Connection = conn; SqlCommand cmd = conn.CreateCommand(); cmd.CommandText = "insert into info values('p005','田泽','0','n004','1990-6-1')"; cmd.ExecuteNonQuery(); conn.Close(); Console.WriteLine("OK");

查询  语句

SqlConnection conn = new SqlConnection("server=.;database=mydb;uid=sa;pwd=123");//连接类            conn.Open();            SqlCommand cmd = conn.CreateCommand();            cmd.CommandText = "select * from info";            SqlDataReader dr = cmd.ExecuteReader();            while (dr.Read())            {                Console.WriteLine(dr[0].ToString()+dr[1].ToString()+dr[2].ToString()+dr[3].ToString()+dr[4].ToString());            }            conn.Close();

用户密码登录 

Console.Write("账号：");            string uid = Console.ReadLine();            Console.Write("密码：");            string pwd = Console.ReadLine();            SqlConnection conn = new SqlConnection("server=.;database=mydb;uid=sa;pwd=123");            conn.Open();            SqlCommand cmd = conn.CreateCommand();            cmd.CommandText = "select * from login where username='"+uid+"'and password='"+pwd+"'";            SqlDataReader dr = cmd.ExecuteReader();            if (dr.HasRows==false)            {                Console.WriteLine("输入的用户密码不正确 请重新输入");                        }            else            {                Console.WriteLine ("登录成功");            }            conn.Close();