/* for insert */
insert into articles (title) values ('insert_test');
select * from articles;
select * from trigger_sample;

/* for udpate */
update articles set title = 'update_test' where id = 1;
select * from articles;
select * from trigger_sample;

/* for delete */
delete from articles where id = 1;
select * from articles;
select * from trigger_sample;