SQL Server ON刪除觸發器

我想創建一個基本的數據庫觸發器，當從database2.table2中刪除一行時，有條件地刪除database1.table1中的行。我是觸發器的新手，希望能夠學習完成這一任務的最佳方式。這是我迄今爲止所擁有的。建議？SQL Server ON刪除觸發器

CREATE TRIGGER sampleTrigger 
    ON database1.dbo.table1 
    FOR DELETE 
AS 
    IF EXISTS (SELECT foo 
       FROM database2.dbo.table2 
       WHERE id = deleted.id 
       AND bar = 4) 

-- If there is a row that exists in database2.dbo.table2 
-- matching the id of the deleted row and bar=4, delete 
-- it as well. 

-- DELETE STATEMENT? 

GO

來源

2012-04-03 Shawn H.

您需要考慮到觸發器被觸發**每個語句**一次（並且** NOT **一次pe r行與許多開發人員相信），並且'Deleted'僞表可能包含**多行**（如果您的語句刪除多行） – 2012-04-03 15:41:40

@marc_s - 在系統中，一次只能刪除一行（應用程序前端）。你能詳細說明你的意思嗎？是否像將WHERE id = deleted.id'更改爲'WHERE id IN（SELECT id FROM FROM）'那樣簡單？ – 2012-04-03 15:52:39

@ShawnH。是的，它應該是那麼簡單。我認爲馬克意味着如果從某處觸發大規模刪除，觸發器只會針對整個語句而不是每行觸發一次，因此使用「IN」應該對其進行排序。 – Bridge 2012-04-03 15:59:35

CREATE TRIGGER sampleTrigger 
    ON database1.dbo.table1 
    FOR DELETE 
AS 
    DELETE FROM database2.dbo.table2 
    WHERE bar = 4 AND ID IN(SELECT deleted.id FROM deleted) 
GO

來源

2012-04-03 15:54:34 Magnus

謝謝。這很簡單，並且像魅力一樣工作。 – 2012-04-03 16:23:10

INSERTED和DELETED是虛擬表。他們需要在FROM條款中使用。

CREATE TRIGGER sampleTrigger 
    ON database1.dbo.table1 
    FOR DELETE 
AS 
    IF EXISTS (SELECT foo 
       FROM database2.dbo.table2 
       WHERE id IN (SELECT deleted.id FROM deleted) 
       AND bar = 4)

來源

2012-04-03 15:53:58

最好使用：

DELETE tbl FROM tbl INNER JOIN deleted ON tbl.key=deleted.key

來源

2013-11-28 01:26:23

我會建議使用exists代替in因爲在某些情況下這意味着空值the behavior is different，所以

CREATE TRIGGER sampleTrigger 
    ON database1.dbo.table1 
    FOR DELETE 
AS 
    DELETE FROM database2.dbo.table2 childTable 
    WHERE bar = 4 AND exists (SELECT id FROM deleted where deleted.id = childTable.id) 
GO

來源

2014-02-14 11:07:17 Narkha

SQL Server ON刪除觸發器

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