今天说说这个文件tnsnames.ora

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

DEV =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = dev)
    )
  )

DBZH =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.8.157)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = dbzh)
    )
  )

INST1_HTTP =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 127.0.0.1)(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)
    )
  )

DB165 =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.8.165)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = db165)
    )
  )

1、执行下面这个命令：
TNSPING  DB165
执行结果：
TNS Ping Utility for 32-bit Windows: Version 9.2.0.1.0 - Production on 21-12月-2
006 15:53:23

Copyright (c) 1997 Oracle Corporation.  All rights reserved.

已使用的参数文件:
E:\oracle\ora92\network\admin\sqlnet.ora

已使用 TNSNAMES 适配器来解析别名
Attempting to contact (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)
(HOST = 192.168.8.165)(PORT = 1521))) (CONNECT_DATA = (SERVICE_NAME = db165)))
OK（20毫秒）
已经可以正常的连接了。

2、如果ORACLE8下面的客户端工具无法使用了，现在可以通过修改这个文件来实现从从本机来连接高版本数据库的作用。
3、在不同版本的oracle之间导入导出数据主义一个原则，需要用oracle低版本的工具导入导出数据。