Boolean Exceptions In PLSQL

declare
   v_foundrows boolean := false;
begin
   for r in ( select * from emp where employee_id= &dno )
   loop
      dbms_output.put_line(r.last_name || ' ' || r.salary);
      v_foundrows := true;
   end loop;

   if not v_foundrows then
      raise no_data_found;
   end if;

exception
   when no_data_found then
      dbms_output.put_line('hello');
end;