创建DBlinksql

create database link jjlink 
connect to 用户民 identified by 密码 
using '(DESCRIPTION = 
(ADDRESS_LIST = 
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.3.54)(PORT = 1521)) 
) 
(CONNECT_DATA = 
(SERVICE_NAME = 实例名) 
) 
)';