**********创建数据库链接******************
create public database link link_gzzl
connect to system identified by "123456"
using '(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.20)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = GZZL)
)
)';
***********从A库取B库的数据
select * from pat_master_index@likn_gzzl;