select * from dba_objects o where object_type='DATABASE LINK';

drop database link remoteOssc--link名字

select * from risenet_out_user_info@remote

SELECT * FROM GLOBAL_NAME; --查看服務名

create database link remoteOssc  --創建link
             --用戶名               --密碼
  connect to user identified by pass
  using '(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = Ip)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = instance)
    )
  )';
select * from risenet_out_user_info@remoteossc