create procedure Insert_Airplane(airplaneName in char, noOfSeat in int, airportID in int)
  is
  idAirplane int;
  begin
    select max(id) into idAirplane from (
          (select id from AIRPLANE1@DATABASE_DUNG)
              union all
          (select id from AIRPLANE2@DATABASE_VU)
              union all
          (select id from AIRPLANE3)
              union all
          (select id from AIRPLANE4@DATABASE_LONG)
        );
        idAirplane := idAirplane + 1;

    if (idAirplane < 5) then --Dung
        insert into AIRPLANE1@DATABASE_DUNG values (idAirplane, airplaneName, noOfSeat, airportID);
    elsif (idAirplane >= 5 and idAirplane < 0 ) then --Vu
        insert into AIRPLANE2@DATABASE_VU values (idAirplane, airplaneName, noOfSeat, airportID);
    elsif (idAirplane >= 10 and idAirplane < 15) then --Trung
        insert into AIRPORT3 values (idAirplane, airplaneName, noOfSeat, airportID);
    elsif (idAirplane >= 15 and idAirplane < 20) then --Long
        insert into AIRPORT4@DATABASE_LONG values (idAirplane, airplaneName, noOfSeat, airportID);
    else
        dbms_output.put_line('Error');
    end if;
  end;
  exec Insert_Airplane('Boeing696', 500, 4);