informix触发器如何编写？最后提供示例。急！急！急！
------解决方案--------------------------------------------------------
CREATE TRIGGER up_price
UPDATE OF unit_price ON stock
REFERENCING OLD AS pre NEW AS post
FOR EACH ROW WHEN(post.unit_price > pre.unit_price * 2)
(INSERT INTO warn_tab
VALUES(pre.stock_num, pre.manu_code, pre.unit_price,
post.unit_price, CURRENT))
看看，有问题提