1. 插入數據前判斷數據是否存在

SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ============================================= -- Author: <Author,,Name> -- Create date: <Create Date,,> -- Description: <Description,,> -- ============================================= alter TRIGGER CategoryExistTrigger ON ProductCategory instead of insert ASdeclare @categoryName varchar(50); BEGIN -- SET NOCOUNT ON added to prevent extra result sets from -- interfering with SELECT statements. SET NOCOUNT ON;-- Insert statements for trigger here select @categoryName = CategoryName from inserted; if exists(select * from ProductCategory where CategoryName =@categoryName) begin print 'Category exists..' end; else begin insert into ProductCategory select * from inserted; end;END

2. 刪除表中數據時需要先刪除外鍵表的數據

SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO -- ============================================= -- Author: <Author,,Name> -- Create date: <Create Date,,> -- Description: <Description,,> -- ============================================= alter TRIGGER DeleteOrderTrigger ON OrderHeader instead of delete AS declare @OrderId varchar(50); BEGINSET NOCOUNT ON; select @OrderId = OrderId from deleted; delete from OrderLine where OrderId = @OrderId;END GO