SQL> select * from v$version;

BANNER
----------------------------------------------------------------
Oracle9i Enterprise Edition Release 9.2.0.1.0 - Production
PL/SQL Release 9.2.0.1.0 - Production
CORE    9.2.0.1.0       Production
TNS for 32-bit Windows: Version 9.2.0.1.0 - Production
NLSRTL Version 9.2.0.1.0 - Production

安装ORACLE的时候默认建了一个SID为OEMREP的数据库，用ODCA新建一个名为TEST的数据库，完成之后打开sqlplus
SQL>sys/orcl@OEMREP as sysdba

ERROR:
ORA-12505: TNS: 监听器无法处理连接描述符中所给出的 SID

察看tnsnames.ora 发现原来的OEMREP数据库的主机字符串没有了，只有TEST的主机字符串

# TNSNAMES.ORA Network Configuration File: C:\oracle\ora92\network\admin\tnsnames.ora
# Generated by Oracle configuration tools.

TEST =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = TLH)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = TEST)
    )
)

INST1_HTTP =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = TLH)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = SHARED)
      (SERVICE_NAME = MODOSE)
      (PRESENTATION = http://HRService)
    )
)

EXTPROC_CONNECTION_DATA =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
    )
    (CONNECT_DATA =
      (SID = PLSExtProc)
      (PRESENTATION = RO)
    )
)

在这个文件中手动加入OEMREP的主机字符串
OEMREP =
(DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = TLH)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SID = OEMREP)
      (SERVER = DEDICATED)
    )
)

察看监听程序配置文件listener.ora,
# LISTENER.ORA Network Configuration File: C:\oracle\ora92\network\admin\listener.ora
# Generated by Oracle configuration tools.

LISTENER =
(DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
      )
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = TLH)(PORT = 1521))
      )
    )
)

SID_LIST_LISTENER =
(SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\ora92)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = TEST)
      (ORACLE_HOME = C:\oracle\ora92)
      (SID_NAME = TEST)
    )
   
)
缺少OEMREP的描述，也就是没有监听OEMREP的服务，修改为
# LISTENER.ORA Network Configuration File: C:\oracle\ora92\network\admin\listener.ora
# Generated by Oracle configuration tools.

LISTENER =
(DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
      )
      (ADDRESS_LIST =
        (ADDRESS = (PROTOCOL = TCP)(HOST = TLH)(PORT = 1521))
      )
    )
)

SID_LIST_LISTENER =
(SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\ora92)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = TEST)
      (ORACLE_HOME = C:\oracle\ora92)
      (SID_NAME = TEST)
    )
    (SID_DESC =
      (GLOBAL_DBNAME = OEMREP)
      (ORACLE_HOME = C:\oracle\ora92)
      (SID_NAME = OEMREP)
    )

)

重新启动TNSListener服务，是改动生效。

连接出错一般都是listener.ora tnsnames.ora配置的问题。

从上面可以看到是用计算机名表示本机地址，在C:\WINDOWS\system32\drivers\etc\hosts中加入本机地址与计算机名的映射关系，加入下面一句
172.19.20.37   TLH

这句不加好像也是可以的，以前没有加过