Question

I would like to use a trigger on a table which will be fired every time a row is inserted, updated, or deleted.

I wrote something like this:

CREATE or REPLACE TRIGGER test001
  AFTER INSERT OR DELETE OR UPDATE ON tabletest001
  REFERENCING OLD AS old_buffer NEW AS new_buffer 
  FOR EACH ROW WHEN (new_buffer.field1 = 'HBP00') 

and it works.
Since I would like to do the same things if the row is inserted, updated, or deleted, I would like to know what’s happening in the trigger.
I think I can manage to find if the row is inserted or updated (I can check the old_buffer with the new_buffer).
How can I know if the row has been deleted?

Answer 1

From Using Triggers:

Detecting the DML Operation That Fired
a Trigger

If more than one type of DML operation
can fire a trigger (for example, ON
INSERT OR DELETE OR UPDATE OF
Emp_tab), the trigger body can use the
conditional predicates INSERTING,
DELETING, and UPDATING to check which
type of statement fire the trigger.

So

IF DELETING THEN ... END IF;

should work for your case.