在 Oracle11g 数据库上，这有效：
SQL> connect USER/pass
Connected.
但是，这不会：
SQL> connect USER/pass@db
ERROR:
ORA-01017: invalid username/password; logon denied
我已经执行了：
SQL> grant connect to USER;
Grant succeeded.
我错过了什么？
tnsnames.ora：
DB =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = a.dom.b.com)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = db)
)
)
编辑：
:> sqlplus USER/pass
SQL*Plus: Release 11.1.0.7.0 - Production on Mon Mar 11 15
Copyright (c) 1982, 2008, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.7.0 - 64bit Production
其他两个没有。
:> sqlplus USER/pass@db
SQL*Plus: Release 11.1.0.7.0 - Production on Mon Mar 11 15:04:44 2013
Copyright (c) 1982, 2008, Oracle. All rights reserved.
ERROR:
ORA-01017: invalid username/password; logon denied
这会产生标识符错误：
:> sqlplus USER/pass@db//localhost:1521
SQL*Plus: Release 11.1.0.7.0 - Production on Mon Mar 11 15:10:38 2013
Copyright (c) 1982, 2008, Oracle. All rights reserved.
ERROR:
ORA-12154: TNS:could not resolve the connect identifier specified
我已经验证了 tnsnames.ora 条目，并且我的 service 拼写正确。
编辑2：
:> lsnrctl status
LSNRCTL for 64-bit Windows: Version 11.1.0.7.0 - Production on 11-MAR-2013 15:14:19
Copyright (c) 1991, 2008, Oracle. All rights reserved.
Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=a.dom.b.com)(PORT=1521
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for 64-bit Windows: Version 11.1.0.7.0 - Production
Start Date 01-MAR-2013 16:15:25
Uptime 9 days 21 hr. 59 min. 8 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File d:\oracle\product\11.1.0\db_1\network\admin\listener.ora
Listener Log File d:\oracle\diag\tnslsnr\TMDEV100\listener\alert\log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=a.dom.b.com)(PORT=1521)))
Services Summary...
Service "db" has 1 instance(s).
Instance "db", status READY, has 1 handler(s) for this service...
...
...
The command completed successfully