Gatilho Oracle SQL na atualização da coluna

create or replace
  TRIGGER ADD_CREATE_DT 
  after UPDATE of approved ON articles 
  for each row
  when (new.approved = 'Y')
  BEGIN
  :new.create_dt := sysdate;
  END;

create or replace
  TRIGGER ADD_CREATE_DT 
  after UPDATE of approved ON articles 
  for each row
  BEGIN
  if :new.approved = 'Y' then
   :new.create_dt := sysdate;
  end if;
  END;