trigger ｕｐｄａｔｅ　demonstration

最新推荐文章于 2025-02-23 15:39:01 发布

原创最新推荐文章于 2025-02-23 15:39:01 发布 · 397 阅读

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#table #object #insert #null #go

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本文介绍了一种使用SQL触发器实现当主表更新时，从表数据自动同步更新的方法。通过具体实例演示了如何创建表、插入数据，并设置触发器以确保数据一致性。

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if object_id ('stu')is not null drop table stu
go
create table stu(
stu_id int primary key
)
go
if object_id('JS') is not null drop table JS
go
create table JS(
js_id int identity(1,1),
stu_id int ,
JS_time datetime,
HS_time datetime
)

go
insert stu
select 1 union all
select 2 union all
select 3 union all
select 4

go
insert JS(stu_id,JS_time)
select 1,getdate() union all
select 2,getdate() union all
select 3,getdate() union all
select 4,getdate()

if exists (select name from sysobjects where name ='update_trigger' and xtype='tr') drop trigger update_trigger
go
create trigger update_trigger
on stu
for update
as
if update (stu_id)
begin
update JS set stu_id =i.stu_id from JS j,deleted d,inserted i
where d.stu_id=j.stu_id
end

update stu set stu_id=10 where stu_id =1

select * from stu
select * from js

support there is two relation table ,when we modify the fist table ,the second table will be modified automatically ~!