在处理多个插入/更新的记录时使用IF-UPDATE-on-SQL触发器

我使用此SQL Server触发器从特定表中查找多条记录的插入/更新，并将其放入另一个队列表中以供稍后处理

ALTER TRIGGER [dbo].[IC_ProductUpdate] ON [dbo].[StockItem]
AFTER INSERT, UPDATE
AS
BEGIN
    SELECT RowNum = ROW_NUMBER() OVER(ORDER BY ItemID) , ItemID
    INTO #ProductUpdates
    FROM INSERTED;

    DECLARE @MaxRownum INT;
    SET @MaxRownum = (SELECT MAX(RowNum) FROM #ProductUpdates);

    DECLARE @Iter INT;
    SET @Iter = (SELECT MIN(RowNum) FROM #ProductUpdates);

    WHILE @Iter <= @MaxRownum
    BEGIN
        -- Get Product Id
        DECLARE @StockItemID INT = (SELECT ItemID FROM #ProductUpdates WHERE RowNum = @Iter);

        -- Proceed If This Product Is Sync-able
        IF (dbo.IC_CanSyncProduct(@StockItemID) = 1)
        BEGIN
            -- Check If There Is A [ProductUpdate] Queue Entry Already Exist For This Product
            IF ((SELECT COUNT(*) FROM IC_ProductUpdateQueue WHERE StockItemID = @StockItemID) > 0)
            BEGIN
                -- Reset [ProductUpdate] Queue Entry
                UPDATE IC_ProductUpdateQueue 
                SET Synced = 0
                WHERE StockItemID = @StockItemID
            END
            ELSE
            BEGIN
                -- Insert [ProductUpdate] Queue Entry
                INSERT INTO IC_ProductUpdateQueue (StockItemID, Synced) 
                VALUES (@StockItemID, 0)
            END
        END

        SET @Iter = @Iter + 1;
    END

    DROP TABLE #ProductUpdates;
END

但是，我不确定如何将其合并到上述触发器中，因为我的触发器也处理同时更新的多行

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有什么想法吗？在触发器的哪一点我可以使用IF UPDATEcolX？

您可以加入到deleted并使用where i.Name D.Name

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你可以加入到已删除并使用where I.Name D.Name

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首先，我建议每个操作有一个单独的触发器——一个用于插入，另一个用于更新。保持代码的整洁，减少IF语句等的混乱

INSERT触发器非常简单，因为不需要检查更新，也不需要临时表和缓慢的WHILE循环，只要两个简单的、基于集合的语句，就可以完成：

CREATE TRIGGER [dbo].[IC_ProductInsert] ON [dbo].[StockItem]
AFTER INSERT
AS
BEGIN
    -- update the queue for those entries that already exist                 
    -- those rows that *DO NOT* exist yet are not being touched
    UPDATE puq
    SET Synced = 0
    FROM dbo.IC_ProductUpdateQueue puq
    INNER JOIN Inserted i ON puq.StockItemID = i.StockItemID

    -- for those rows that don't exist yet - insert the values
    INSERT INTO dbo.IC_ProductUpdateQueue (StockItemID, Synced) 
        SELECT 
            i.StockItemID, 0
        FROM
            Inserted i
        WHERE 
            NOT EXISTS (SELECT * FROM dbo.IC_ProductUpdateQueue puq
                        WHERE puq.StockItemID = i.StockItemID)
END

更新触发器需要进行一次额外的检查，以查看两列中的一列是否已更改。通过将插入的伪表与更新后的新值相结合，以及将删除的伪表与更新前的旧值相结合，可以非常轻松地处理此问题：

---

首先，我建议每个操作有一个单独的触发器——一个用于插入，另一个用于更新。保持代码的整洁，减少IF语句等的混乱

INSERT触发器非常简单，因为不需要检查更新，也不需要临时表和缓慢的WHILE循环，只要两个简单的、基于集合的语句，就可以完成：

CREATE TRIGGER [dbo].[IC_ProductInsert] ON [dbo].[StockItem]
AFTER INSERT
AS
BEGIN
    -- update the queue for those entries that already exist                 
    -- those rows that *DO NOT* exist yet are not being touched
    UPDATE puq
    SET Synced = 0
    FROM dbo.IC_ProductUpdateQueue puq
    INNER JOIN Inserted i ON puq.StockItemID = i.StockItemID

    -- for those rows that don't exist yet - insert the values
    INSERT INTO dbo.IC_ProductUpdateQueue (StockItemID, Synced) 
        SELECT 
            i.StockItemID, 0
        FROM
            Inserted i
        WHERE 
            NOT EXISTS (SELECT * FROM dbo.IC_ProductUpdateQueue puq
                        WHERE puq.StockItemID = i.StockItemID)
END

更新触发器需要进行一次额外的检查，以查看两列中的一列是否已更改。通过将插入的伪表与更新后的新值相结合，以及将删除的伪表与更新前的旧值相结合，可以非常轻松地处理此问题：

---

可能的重复可能的重复这正是我在寻找和感谢的信息。为了其他人的利益，我想补充一点，加入到已删除的表示更新之前的旧值，并且没有记录被实际删除。这正是我所寻找的，非常感谢这些信息。为了其他人的缘故，我想补充一点，join to deleted表示更新之前的旧值，并且实际上没有删除任何记录。

ALTER TRIGGER [dbo].[IC_ProductUpdate] ON [dbo].[StockItem]
AFTER UPDATE
AS
BEGIN
    -- update the queue for those entries that already exist                 
    -- those rows that *DO NOT* exist yet are not being touched
    UPDATE puq
    SET Synced = 0
    FROM dbo.IC_ProductUpdateQueue puq
    INNER JOIN Inserted i ON puq.StockItemID = i.StockItemID
    INNER JOIN Deleted d ON d.StockItemID = i.StockItemID
    WHERE
        i.Name <> d.Name OR i.Description <> d.Description

    -- for those rows that don't exist yet - insert the values
    INSERT INTO dbo.IC_ProductUpdateQueue (StockItemID, Synced) 
        SELECT 
            i.StockItemID, 0
        FROM
            Inserted i
        INNER JOIN 
            Deleted d ON d.StockItemID = i.StockItemID
        WHERE 
            i.Name <> d.Name OR i.Description <> d.Description
            AND NOT EXISTS (SELECT * FROM dbo.IC_ProductUpdateQueue puq
                            WHERE puq.StockItemID = i.StockItemID)
END