class Program

     {

         private static string constr = "server=.;database=northwnd;integrated security=sspi";

         static void Main(string[] args)

         {

             string source = "provider=sqloledb;" + constr;

             string select = "select contactname,companyname from customers";

             OleDbConnection con = new OleDbConnection(source);

             con.Open();

             OleDbCommand cmd = new OleDbCommand(select, con);

             OleDbDataReader reader = cmd.ExecuteReader();

             while (reader.Read())

                 Console.WriteLine("{0} from {1}", reader.GetString(0), reader.GetString(1));

             reader.Close();

             con.Close();

         }

     }