Connection String and Connection Class File

Include the following lines in the configuration section of web.config file.

<appSettings>
   <add key="con" value="Server = My Server name; Initial Catalog= My Database name; User ID = abcd; Password = *****;"/>
</appSettings>

Add a class file by right clicking on the project -- Add -- Class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
namespace WebApplication1 {
    public class code {
        SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["con"].ToString());
        public DataSet select(string s) {
            DataSet ds = new DataSet();
            SqlDataAdapter da = new SqlDataAdapter(s, con);
            da.Fill(ds);
            return ds;
        }
        public int insert(string s) {
            int i;
            SqlCommand cmd = new SqlCommand(s, con);
            con.Open();
            i = cmd.ExecuteNonQuery();
            con.Close();
            return i;
        }
    }
}

Note: In the webform, just create an object for the connection class file, thus reducing the complexity of the code........!!