suppress frm-40208 form running in query-only mode message

In the On-ERROR trigger write:-

  al_id     Alert;
al_button Number;

BEGIN
if errcode=40208 then
--do nothing;
else
     
      al_button := Show_Alert( 'Error_Alert' );
      RAISE FORM_TRIGGER_fAILURE;
   end if;  
end;