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我必须为Apache Derby编写一个sql更新触发器语句。我通常使用Sql Server和T-SQL。但现在我必须使用德比。不幸的是,我对德比很陌生,在德比手册中找不到合适的解决方案。CREATE TRIGGER随着Derby中的条件
我的问题是,我必须检查更新触发器中的条件,并基于此条件的结果,我将执行UPDATE或INSERT,因此在T-SQL中,我将使用IF-ELSE-条件。有人能告诉我什么是德比或者其他方式吗?我已经考虑过WHEN条款,但这似乎是错误的方向。
我有下面的代码至今:
CREATE TRIGGER UPDATE_EVENTS
AFTER UPDATE
ON ACCIDENTS
REFERENCING OLD AS oldRow NEW AS newRow
FOR EACH ROW MODE DB2SQL
-- In the following, I would usually use an IF-ELSE Statement,
-- but I can't use this in Derby. So I tried the optional WHEN Statement,
-- but there I could not have an else "path", right?
-- This should be the If-Case
WHEN((SELECT COUNT(*) FROM VIEW_EVENTS WHERE ID_DATE = newRow.ID_DATE) > 0)
UPDATE VIEW_EVENTS
SET DETAILS = newRow.DETAILS,
PARTICIPANTS = newRow.PARTICIPANTS
WHERE ID_DATE = newRow.ID_DATE
-- And this should be the else case
WHEN((SELECT COUNT(*) FROM VIEW_EVENTS WHERE ID_DATE = newRow.ID_DATE) <= 0)
INSERT INTO VIEW_EVENTS
(ID_KEY,
ID_DATE,
DETAILS,
PARTICIPANTS
)
VALUES
(newRow.ID_KEY,
newRow.ID_DATE,
newRow.DETAILS,
newRow.PARTICIPANTS
);
这种说法只是一个小例子来向你展示我的问题。我希望你可以帮助我 :)。
最好的问候,
亚尔钦