Oracle SQL trigger on update of column

Question

I\'m trying to create a trigger for my table which automatically adds a published date based on when a certain flag is set to \'Y\'

I don\'t have much experience wit

Answer 1

Use the WHEN clause:

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;

Or use IF:

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;

In this case, WHEN is more appropriate and efficient.