连接SID相同数据库实例，这两个实例在不同的服务器上
例如我的tnsnames 文件
# tnsnames.ora Network Configuration File: D:\oracle\product\10.2.0\db_1\NETWORK\ADMIN\tnsnames.ora
# Generated by Oracle configuration tools.
DEV =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 10.4.247.92)(PORT = 1521))
)
(CONNECT_DATA =
(SERVICE_NAME = DEV)
)
)
ORCL =
(DESCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
)
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = orcl)
)
)
EXTPROC_CONNECTION_DATA =
(DEoracle账号SCRIPTION =
(ADDRESS_LIST =
(ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1))
)
(CONNECT_DATA =
(SID = PLSExtProc)
(PRESENTATION = RO)
)
)
红色部分就是相同的实例名（实质上是不同的数据库服务）。
另一个描述符起个和上一个描述符不同的名称就行。。。。