Question

如何写一个ORACLE触发器同步两个表中的数据？

比如A表中的aa字段值发生改变时触发B表中同为aa字段的值也同步更改？本人菜鸟初学急用 见笑了

Answer 1

--即时同步两个表的实例:

--测试环境:SQL2000,远程主机名:xz,用户名:sa,密码:无,数据库名:test

--创建测试表,不能用标识列做主键,因为不能进行正常更新
--在本机上创建测试表,远程主机上也要做同样的建表操作,只是不写触发器
if exists (select * from dbo.sysobjects where id = object_id(N'[test]') and OBJECTPROPERTY(id, N'IsUserTable') = 1)
drop table [test]

create table test(id int not null constraint PK_test primary key
,name varchar(10))
go

--创建同步的触发器
create trigger t_test on test
for insert,update,delete
as
set XACT_ABORT on
--启动远程服务器的MSDTC服务
exec master..xp_cmdshell 'isql /S"xz" /U"sa" /P"" /q"exec master..xp_cmdshell ''net start msdtc'',no_output"',no_output

--启动本机的MSDTC服务
exec master..xp_cmdshell 'net start msdtc',no_output

--进行分布事务处理,如果表用标识列做主键,用下面的方法
BEGIN DISTRIBUTED TRANSACTION
delete from openrowset('sqloledb','xz';'sa';'',test.dbo.test)
where id in(select id from deleted)
insert into openrowset('sqloledb','xz';'sa';'',test.dbo.test)
select * from inserted
commit tran
go

--插入数据测试
insert into test
select 1,'aa'
union all select 2,'bb'
union all select 3,'c'
union all select 4,'dd'
union all select 5,'ab'
union all select 6,'bc'
union all select 7,'ddd'

--删除数据测试
delete from test where id in(1,4,6)

--更新数据测试
update test set name=name+'_123' where id in(3,5)

--显示测试的结果
select * from test a full join
openrowset('sqloledb','xz';'sa';'',test.dbo.test) b on a.id=b.id

追问

我说的是ORACLE

Answer 2

CREATE OR REPLACE TRIGGER trg_A
after update
of aa
ON a
referencing new as new old as old
for each row
declare

begin
if :new.aa<>:old.aa then
update B set aa=:new.aa where A.XX=B.XX;
end if;

exception
when others then
null;
end trg_A;

Answer 3

楼上已经回答得非常到位了。