问题环境：
1、数据库版本： Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
2、操作系统环境：Windows 7 旗舰版 64位
3、本地安装有4个Oracle 数据库软件【四个数据库软件，不是四个数据库哦】如下：
Oracle 10.2服务端软件：e:oracleproduct10.2.0db_1BINsqlplus.exe
Oracle 11.2服务端软件：e:oracleproduct11.2.0db_1BINsqlplus.exe
Oracle 10.2客户端软件：e:oracleproduct11.2.0client_1BINsqlplus.exe
Oracle 11.2客户端软件：e:oracleproduct10.2.0client_1BINsqlplus.exe
问题描述：
1、本地启动Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 ,服务名sun，服务状态如下：
C:Windowssystem32>sc query oracleservicesun
SERVICE_NAME:oracleservicesun
TYPE : 10 WIN32_OWN_PROCESS
STATE : 4 RUNNING
(STOPPABLE, PAUSABLE, ACCEPTS_SHUTDOWN)
WIN32_EXIT_CODE : 0 (0x0)
SERVICE_EXIT_CODE : 0 (0x0)
CHECKPOINT : 0x0
WAIT_HINT : 0x0
2、使用Oracle 10.2服务端软件可以正常连接数据库，如下：C:Windowssystem32>set ORACLE_SID=sun
C:Windowssystem32>e:oracleproduct10.2.0db_1BINsqlplus.exe / as sysdba
SQL*Plus: Release 10.2.0.4.0- Production on 星期一 5月 14 17:06:32 2012
Copyright (c) 1982, 2007, Oracle. All Rights Reserved.
连接到:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
sys@SUN>
3、使用Oracle 11.2服务端软件可以正常连接数据库，如下：C:Windowssystem32>set ORACLE_SID=sun
C:Windowssystem32>e:oracleproduct11.2.0db_1BINsqlplus.exe / as sysdba
SQL*Plus: Release 11.2.0.1.0Production on 星期一 5月 14 17:07:23 2012
Copyright (c) 1982, 2010, Oracle. All rights reserved.
连接到:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
sys@SUN>
4、使用Oracle 10.2客户端软件可以正常连接数据库，如下：
C:Windowssystem32>set ORACLE_SID=sun
C:Windowssystem32>E:oracleproduct10.2.0client_1BINsqlplus.exe / as sysdba
SQL*Plus: Release 10.2.0.4.0- Production on 星期一 5月 14 17:11:27 2012
Copyright (c) 1982, 2007, Oracle. All Rights Reserved.
连接到:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
sys@SUN>
5、使用Oracle 11.2客户端软件无法连接数据库，如下
C:Windowssystem32>set ORACLE_SID=sun
C:Windowssystem32>e:oracleproduct11.2.0client_1BINsqlplus.exe / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on 星期一 5月 14 17:13:08 2012
Copyright (c) 1982, 2010, Oracle. All rights reserved.
ERROR:
ORA-12560: TNS: 协议适配器错误
请输入用户名:
补充信息：
Oracle 11.2客户端sqlnet.ora文件如下：
# sqlnet.ora Network Configuration File: e:oracleproduct11.2.0client_1networkadminsqlnet.ora
# Generated by Oracle configuration tools.
# This file is actually generated by netca. But if customers choose to
# install "Software Only", this file wont exist and without the native
# authentication, they will not be able to connect to the database on NT.
SQLNET.AUTHENTICATION_SERVICES= (NTS)
NAMES.DIRECTORY_PATH= (TNSNAMES, EZCONNECT)
请各位湿湿们不吝赐教，折腾了很久也没搞明白原因，纠结中。。