如果我在 CANINES 表上有一个更新前触发器,它将时间戳列设置为 now(),并且 DOGS 从 CANINES 继承,那么当更新 DOGS 行时,CANINES 更新触发器是否应该触发?在我的测试中它没有,所以我怀疑答案是否定的,但也许我没有正确地做事:
create table canines
(
lastupdate timestamp with time zone default now()
);
CREATE OR REPLACE FUNCTION stamp_lastupdate_column()
RETURNS TRIGGER AS $$
BEGIN
NEW.lastupdate = now();
RETURN NEW;
END;
$$ language 'plpgsql';
CREATE TRIGGER TRG_CANINES_BU BEFORE UPDATE
on CANINES FOR EACH ROW EXECUTE PROCEDURE
stamp_lastupdate_column();
create table dogs
(id int primary key,
breed varchar(25)
) inherits (CANINES);
insert into dogs(id, breed) values(1, 'sheltie');
select * from dogs;
--"2013-02-09 06:49:31.669-05" , 1 , sheltie
update dogs set breed = 'Sheltie/Shetland Sheepdog' where id = 1;
select * from dogs;
--"2013-02-09 06:49:31.669-05" , 1 , Sheltie/Shetland Sheepdog