create public database link Heng
connect to TRADE identified by "trade"
using ‘(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.224.200.122)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = orcl)
)
)‘;
原文：https://www.cnblogs.com/joesenno1/p/15033390.html