id not getting incremented in database in c#asp.net webapplication

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ASP.NET

In userlogin history i want to dispaly the records according to username,logintime ,logouttime,formname(what all the forms users so long visited list)but here the id(i.e in my project i am using uno) is not getting incremented in database how to make it to get increment..can anyone help me with this. Following is my code:

protected void Page_Load(object sender, EventArgs e)
   {
       int uno = 0;
       SqlConnection con = new SqlConnection(ConfigurationManager.AppSettings["constr"]);
       con.Open();
       string s = "select max(uno) as uno from PayLoginHistory";
       SqlDataAdapter da = new SqlDataAdapter(s, con);
       DataTable dt = new DataTable();
       da.Fill(dt);
       if (dt.Rows.Count > 1)
       {
          uno = uno + 1;
       }
       if (Convert.ToString(uno) == "")
       {
           uno = uno + 1;
       }
       else
       {
           uno = uno + 1;
       }
       Session["uno"] = Convert.ToString(uno);
   }