沈丘杀人案,於书凝,康洁 邓楠
1. 插入数据前判断数据是否存在
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 as declare @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. 删除表中数据时需要先删除外键表的数据
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); begin set nocount on; select @orderid = orderid from deleted; delete from orderline where orderid = @orderid; end go
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数据库SQL---数据库、基本表、视图、索引的定义、修改、删除
在 Azure CentOS VM 中配置 SQL Server 2019 AG - (上)
在 Azure CentOS VM 中配置 SQL Server 2019 AG - (下)
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