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 with creating triggers but so far this is what i’ve got

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

I get this error when updating the column

trigger ‘USER.ADD_CREATE_DT’ is invalid and failed re-validation

Any ideas?

Thanks

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.