触发器批量业务操作实现方式 update触发器用游标处理

USE [Test]
GO
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
        ALTER  TRIGGER [dbo].[trg_InsertAndUpdate]
        ON [dbo].[Shop_OrderAmount]
        FOR UPDATE 
        AS
        BEGIN 
        SET NOCOUNT ON;
        declare    @oldQty int,
        @newQty  int,
        @ShopGid uniqueidentifier,
        @ProdGid uniqueidentifier,
        @tempShop Nvarchar(MAX)
        --更新前的数据
        select @oldQty=Qty,
        @ShopGid =ShopGid,
        @ProdGid=ProdGid
         from deleted; 

        BEGIN
        --更新后的数据            
        select @newQty = Qty  from inserted;
        --声明游标
        declare cursorShopQty cursor  for 
        (select  DISTINCT A.Gid  from inserted A
        inner join deleted B on A.Gid=B.Gid
        )
        --打开游标--
        open  cursorShopQty 
        --开始循环游标变量--
        fetch next from cursorShopQty into @tempShop
        --返回被 FETCH语句执行的最后游标的状态--    
        while @@FETCH_STATUS = 0    
        if  (update(Qty) and @newQty<>@oldQty)
        BEGIN            
        INSERT INTO Shop_OrderLog
        (Gid,ShopGid,ProdGid,Qty,UserQty, CreateDate)
        select NEWID(),
        B.Gid,B.ShopGid,B.ProdGid,B.Qty, isnull(A.Qty,0)-ABS(B.Qty),
        GETDATE()
        from inserted A   inner join deleted B on A.Gid=B.Gid   where  A.Gid=@tempShop
          --转到下一个游标，没有会死循环       
        fetch next from cursorShopQty into @tempShop   
        END   
        close cursorShopQty  --关闭游标
        deallocate cursorShopQty   --释放游标
        END
        END

游标处理：触发器中DELETE和INSERTED其实是两张虚表，因此用变量获取仅能得到一条数据，但是如果用游标的话可以获取到位于虚表中的所有数据，批量处理

USE [Test]
GO

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
        ALTER  TRIGGER [dbo].[trg_InsertAndUpdate]
        ON [dbo].[Shop_OrderAmount]
        FOR UPDATE 
        AS
        BEGIN 
        SET NOCOUNT ON;
        declare    @oldQty int,
        @newQty  int,
        @ShopGid uniqueidentifier,
        @ProdGid uniqueidentifier
        
        --更新前的数据
        select @oldQty=Qty,
        @ShopGid =ShopGid,
        @ProdGid=ProdGid
         from deleted; 

        BEGIN
        --更新后的数据            
        select @newQty = Qty  from inserted;
        
        if  (update(Qty) and @newQty<>@oldQty)
        BEGIN            
        INSERT INTO Shop_OrderLog
        (Gid,ShopGid,ProdGid,Qty,UserQty, CreateDate)
        select NEWID(),
        B.Gid,B.ShopGid,B.ProdGid,B.Qty, isnull(A.Qty,0)-ABS(B.Qty),
        GETDATE()
        from inserted A   inner join deleted B on A.Gid=B.Gid  
         
        END
        END

未使用游标处理：触发器中DELETE和INSERTED是两张虚表，那么其实上述的操作也可以这么来