ADO.NET怎删改+vs 2013 C#

一、删除

string constr = "server=.;database=test;uid=sa;pwd=sa";
            SqlConnection myconnection = new SqlConnection(constr);
            myconnection.Open();
            string sql = "delete from students where ID=5";
            SqlCommand sc = new SqlCommand(sql,myconnection);
            sc.ExecuteNonQuery();
            SqlDataAdapter sda = new SqlDataAdapter("select * from students",myconnection);
            System.Data.DataSet dr = new System.Data.DataSet();
            sda.Fill(dr,"students");
            sda.Update(dr,"students");
            ViewBag.students = dr.Tables[0];
            return View();

二、插入
            string constr = "server=.;database=test;uid=sa;pwd=sa";
            SqlConnection myconnection = new SqlConnection(constr);
            myconnection.Open();
            string sql1 = "insert into students(sno,name,sex,age) values('101411','历历','男','18')";
            SqlCommand sc = new SqlCommand(sql1, myconnection);
            sc.ExecuteNonQuery();
            string sql = "select * from students";
            SqlDataAdapter sda = new SqlDataAdapter(sql,myconnection);
            System.Data.DataSet ds = new System.Data.DataSet();
            sda.Fill(ds,"students");
            ViewBag.students = ds.Tables[0];
            return View();

三、更新
            string constr = "server=.;database=test;uid=sa;pwd=sa";
            SqlConnection myconnection = new SqlConnection(constr);
            myconnection.Open();
            string sql1 = "update students set sno='1',name='华华' where ID=2";
            SqlCommand sc = new SqlCommand(sql1, myconnection);
            sc.ExecuteNonQuery();
            string sql = "select * from students";
            SqlDataAdapter sda = new SqlDataAdapter(sql, myconnection);
            System.Data.DataSet ds = new System.Data.DataSet();
            sda.Fill(ds, "students");
            ViewBag.students = ds.Tables[0];
            return View();