change the code into three tier

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C#

C#4.0

I have a code in my ui

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["ct"].ConnectionString);
try
{
  con.Open();
}
catch (SqlException ex)
{
  Response.Write(ex.ToString());
}
DataTable dt = new DataTable();
string query = "select column_name from information_schema.columns where table_name ='" + Session["name"] + "' " + "order by ordinal_position";
SqlDataAdapter sda = new SqlDataAdapter(query, con);
sda.Fill(dt);
string ColumnsName_String = "";
for (int i = 0; i <= dt.Rows.Count - 1; i++)
{
  ColumnsName_String = ColumnsName_String + "," + dt.Rows[i]["column_name"];
  if (ColumnsName_String.StartsWith(","))
  {
    ColumnsName_String = ColumnsName_String.Remove(0, 1);
  }
  dl.table_name = Session["name"].ToString();
  dl.column_name = ColumnsName_String.ToString();
  bl.updatedata(dl);
}

i wants change it into three tier
can u help me????

[edit] code tags and tabulation [/edit]