需求：源数据库用户表中用户密码和用户名更改时需要将远程数据库中的用户名和密码更新；
做法：
1、创建数据库连接：两种办法：
1）、在源数据安装文件tnsnames.ora中添加目的数据库信息如下图所示：
ORCLmdsjk =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 193.193.193.209)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = orcl)//目的数据库的服务名；可通过 sqlplus>show parameter service_name 查看
)
)
在源数据库总创建数据库链接：
create database link linkname connect to username identified by userpassword using 'ORCLmdsjk ';
2:）、create database link linkname
connect to username
identified by password
using '(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=193.193.193.209) (PORT=2521)))(CONNECT_DATA=(SERVICE_NAME=orcl)))';
2、在源数据库中建立触发器：
create or replace trigger xyzsk_user_sys_trigger
after insert or update or delete on sec_user
for each row
declare
-- local variables here
flag number;
--如果与209服务器断开连接则不进行数据同步
network_remaining EXCEPTION;
PRAGMA EXCEPTION_INIT(network_remaining, -12560);
begin
if inserting then
insert into xt_users@xyzskxtorcl(id,username,fullname,password,enabled)
values(:new.ID_,:new.NUMBER_,:new.NAME_,:new.PASSWORD_,:new.enable_);
end if;
if updating then
select count(*) into flag from xt_users@xyzskxtorcl where username = :old.NUMBER_;
if(flag is null or flag = 0)then
insert into xt_users@xyzskxtorcl(id,username,fullname,password,enabled)
values(:new.ID_,:new.NUMBER_,:new.NAME_,:new.PASSWORD_,:new.enable_);
else
update xt_users@xyzskxtorcl set username = :new.NUMBER_,fullname=:new.NAME_,password = :new.PASSWORD_
where username = :old.NUMBER_;
end if;
end if;
if deleting then
delete from xt_users@xyzskxtorcl where username = :old.NUMBER_;
end if;
exception
when network_remaining then null;
end xyzsk_user_sys_trigger;
如此即可。
注意：修改数据库文件tnsnames.ora 不需要重新启动数据库即可。