Question

我按名称触发了一个表：[OfficeAutomation_Letter] 更新的表格，每行更新另一次但是当更新命令我运行到两行时会触发错误我需要解释过道的每一行如何发展

我的触发器是：

ALTER TRIGGER [dbo].[Letter_UPD] ON [dbo].[OfficeAutomation_Letter] 
FOR UPDATE
AS

Declare @LetterID int
SELECT @LetterID = ID From Inserted

BEGIN           
    UPDATE OfficeAutomation_TempLetter 
    SET Archived = (Select Archive From Inserted ),
    OriginalNumber = (Select OriginalNumber From Inserted )
    WHERE LetterID = @LetterID          
END

更新我的命令是：

update OfficeAutomation_Letter set OriginalNumber=100 where ID in (3,4)

访问错误是：

    Subquery returned more than 1 value. This is not permitted when
 the subquery follows =, !=, <, <= , >, >= or when the subquery 
is used as an expression.

Answer 1

触发器每个语句运行一次，而不是每行一次，插入和删除的伪表包含所有受影响的行。

ALTER TRIGGER [dbo].[Letter_UPD] ON [dbo].[OfficeAutomation_Letter] 
FOR UPDATE
AS
    UPDATE otl
    SET Archived = i.Archive,
    OriginalNumber = i.OriginalNumber
    FROM
      OfficeAutomation_TempLetter otl
         inner join
      inserted i
         on
            otl.LetterID = i.ID

所以，在原始触发器中，我们有：

SELECT @LetterID = ID From Inserted

将分配一个受影响的行的ID（哪一个，谁知道？ - 未定义）

然后

SET Archived = (Select Archive From Inserted ),
OriginalNumber = (Select OriginalNumber From Inserted )

这是您看到的错误的实际原因，因为右侧的选择将返回多行。

更新两行更新触发器问题

1 个答案: