11g通过一个参数设置密码大小写敏感，下面来做个试验：

C:\Documents and Settings\guogang>sqlplus gg_test/gg_test@10.10.15.25_gg
sql*Plus: Release 10.2.0.1.0 - Production on 星期一 8月 4 17:54:19 2014
Copyright (c) 1982,2005,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
sql> select * from v$version;
BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
PL/sql Release 11.2.0.1.0 - Production
CORE 11.2.0.1.0 Production
TNS for Linux: Version 11.2.0.1.0 - Production
NLSRTL Version 11.2.0.1.0 - Production
sql> show parameter sec_case_sensitive_logon
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sec_case_sensitive_logon boolean TRUE

C:\Documents and Settings\guogang>sqlplus gg_test/gg_tesT@10.10.15.25_gg
sql*Plus: Release 10.2.0.1.0 - Production on 星期一 8月 4 17:54:06 2014
Copyright (c) 1982,Oracle. All rights reserved.
ERROR:
ORA-01017: invalid username/password; logon denied
请输入用户名:

C:\Documents and Settings\guogang>sqlplus gg_test/gg_test@10.10.15.25_gg
sql*Plus: Release 10.2.0.1.0 - Production on 星期一 8月 4 17:52:35 2014
Copyright (c) 1982,Data Mining and Real Application Testing options
sql> alter system set sec_case_sensitive_logon=false;
系统已更改。

sql> 从 Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning,Data Mining and Real Application Testing options 断开

C:\Documents and Settings\guogang>sqlplus gg_test/gg_tesT@10.10.15.25_gg
sql*Plus: Release 10.2.0.1.0 - Production on 星期一 8月 4 17:53:48 2014
Copyright (c) 1982,Data Mining and Real Application Testing options
sql> show parameter sec_case_sensitive_logon
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
sec_case_sensitive_logon boolean FALSE