ora-12514:TNS:listener does not currently know of service requested in connect descriptor
其中LISTENER.ORA文件如下，tnsping正常，服务监听都已开启，解决方法如下
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = E:\oracle\product\10.2.0\db_1)
(PROGRAM = extproc)
)
)
将上面LISTENER.ORA文件中相应部分改为如下：
SID_LIST_LISTENER =
(SID_LIST =
(SID_DESC =
(SID_NAME = PLSExtProc)
(ORACLE_HOME = E:\oracle\product\10.2.0\db_1)
(PROGRAM = extproc)
) (SID_DESC =
(GLOBAL_DBNAME = ORCL)
(ORACLE_HOME = E:\oracle\product\10.2.0\db_1)
(SID_NAME = ORCL)
)
)
然后重启服务和listener，问题解决