update gridview row records in asp.net?

protected void GridView2_RowUpdating(object sender, GridViewUpdateEventArgs e)
    {
        SqlConnection a = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);
        a.Open();
        string cartCmd = "update tbldata set status='Y' where status='N'";
        SqlCommand cmd = new SqlCommand(cartCmd, a);
        SqlDataAdapter sda = new SqlDataAdapter(cmd);
        DataSet ds = new DataSet();
        sda.Fill(ds);
        GridView2.DataSource = ds;
        GridView2.DataBind();
        a.Close();
    }