Stand-alone SELECT statements
Suppose you define the following Select trigger on a table:
CREATE TRIGGER hits_trig SELECT OF col_a ON tab_a
REFERENCING OLD AS hit
FOR EACH ROW (INSERT INTO hits_log
VALUES (hit.col_a, CURRENT, USER));
A
Select trigger executes when the triggering column appears in the
select list of a stand-alone SELECT statement. The following statement
executes a triggered action on the hits_trig trigger for each
instance of a row that the database server returns:
SELECT col_a FROM tab_a;