Sql Connection with select command in asp.net

using System;         

usingSystem.Collections.Generic;

using System.Linq; 

using System.Web;

using System.Web.UI;  

using System.Web.UI.WebControls;

using System.Data;   

using System.Data.SqlClient;

// Using System.Data.OralceClient;

public partial class _Default : System.Web.UI.Page

{      protected void Page_Load(objectsender, EventArgs e)

    {

        // First Trick

        SqlConnection con = newSqlConnection(@"Data Source=ITIKA-PC\SQLEXPRESS;Initial Catalog=Simple;Integrated Security=True");

        con.Open();

        SqlCommand cmd = newSqlCommand("Select *from ProductTable", con);

        SqlDataReader dr = cmd.ExecuteReader();

        GridView1.DataSource = dr;

        GridView1.DataBind();

        con.Close();

   

  // Second Trick Connection Open and Close Using Statement

 using (SqlConnectioncon = new SqlConnection(@"Data Source=ITIKA-PC\SQLEXPRESS;Initial Catalog=Simple;Integrated Security=True"))

        {

            SqlCommand cmd = newSqlCommand("Select *from ProductTable", con);

            con.Open();

            SqlDataReader dr = cmd.ExecuteReader();

            GridView1.DataSource = dr;

            GridView1.DataBind();

        }

       

// 2    Code For Oracle Database

      /*

        OracleConnection con = new OracleConnection(@"Data Source=ITIKA-PC\SQLEXPRESS;Initial Catalog=Simple;Integrated Security=True");

        con.Open();

        OracleCommand cmd = new OracleCommand("Select *from ProductTable", con);

        OracleDataReader dr = cmd.ExecuteReader();

        GridView1.DataSource = dr;

        GridView1.DataBind();

        con.Close();

    */

    }  

 }