---创建dblink,dblink_test名称，（被同步数据库的a_test）ST10766用户名，ep密码，ass100连接字符串
create public database link dblink_test
　　 connect to ST10766 identified by ep
　　 using 'ass100';

---删除dblink
----drop public database link dblink_test;

----建立表
create table a_test (id int,name varchar(20),pass varchar(20))
select * from a_test;

insert into a_test (id,name,pass) values (1,'zzn','shanshan')
insert into b_test (id,username,password) values('1','zxl','xiaolan')

----在目的数据库上，测试dblink，查询的是源数据库的表
select * from a_test@dblink_orc10;?
select * from a_test;

----创建触发器

create or replace trigger a_b_test
? after? insert or update or delete
? on a_test
? for each row
begin
? if deleting then
????? delete from b_test where id=:old.id;
? end if;
? if inserting then
????? insert into b_test(id,username,password)? //b_test表的字段
????? values(:new.id,:new.name,:new.pass);?//a_test表的字段
? end if;
? if updating then
???? update b_test set username=:new.name,password=:new.pass where id=:old.id;
? end if;
end a_b_test;

创建同义词语法:

create synonym? synonym_name for? object_name;

create synonym synonym_name for ;