在Oracle的11g之前的版本中密碼是不區分大小寫的（使用雙引號強制除外）。

在Oracle的11g以及以後的版本中對此有所增強。從此密碼有了大小寫的區分。

這個大小寫敏感特性是通過SEC_CASE_SENSITIVE_LOGON參數來控制的。

1.Oracle 11gR2官方文檔解釋:

http://download.oracle.com/docs/cd/E11882_01/server.112/e10820/initparams218.htm#REFRN10299

SEC_CASE_SENSITIVE_LOGON
Property    Description
Parameter type  Boolean
Default value   true
Modifiable  ALTER SYSTEM
Range of values true | false
Basic   No

SEC_CASE_SENSITIVE_LOGON enables or disables password case sensitivity in the database.
Values:
true
Database logon passwords are case sensitive.
false
Database logon passwords are not case sensitive.
 

2.測試一下

[oracle@localhost ~]$ sqlplus / as sysdba

SQL*Plus: Release 11.2.0.4.0 Production on Mon Feb 12 16:14:53 2018

Copyright (c) 1982, 2013, Oracle.  All rights reserved.


Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

#創建用n1 密碼 ni
SQL> create use n1  identified by n1;
SQL> grant connect,resource to n1;

#查看sec_case_sensitive_logon 參數設置 默認是 TRUE 即開啟登陸大小寫敏感！
SQL> show parameter sec

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_securefile                        string      PERMITTED
optimizer_secure_view_merging        boolean     TRUE
sec_case_sensitive_logon             boolean     TRUE
sec_max_failed_login_attempts        integer     10
sec_protocol_error_further_action    string      CONTINUE
sec_protocol_error_trace_action      string      TRACE
sec_return_server_release_banner     boolean     FALSE
sql92_security                       boolean     FALSE

#使用大寫的密碼登陸 登陸失敗
SQL> conn  n1/N1
ERROR:
ORA-01017: invalid username/password; logon denied


Warning: You are no longer connected to ORACLE.
SQL> conn / as sysdba
Connected.


#動態修改系統參數 為 false 不驗證大小寫
SQL> alter system set sec_case_sensitive_logon = false;

System altered.

#再次使用大寫密碼登陸 成功
SQL> conn n1/N1
Connected.
 

3.延伸測試(sec_case_sensitive_logon 參數只是控制登陸時是否校驗大小寫,密碼還是會進按照世紀的大小寫進行存儲的！)

SQL> show  parameter sec_case_sensitive_logon

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
sec_case_sensitive_logon             boolean     FALSE


#創建用戶 密碼包含大小寫
SQL> create user test11 identified by testAbcD ;

User created.

SQL> grant  connect to test11;

Grant succeeded.


#測試鏈接 大小寫不敏感
SQL> conn  test11/testabcd
Connected.
SQL> conn  / as sysdba
Connected.

#修改為大小寫敏感
SQL> alter system set sec_case_sensitive_logon = true;

System altered.

#用錯誤的密碼無法登陸
SQL> conn  test11/testabcd
ERROR:
ORA-01017: invalid username/password; logon denied


Warning: You are no longer connected to ORACLE.

#包含大小寫的密碼,登陸成功！
SQL> conn test11/testAbcD
Connected.
SQL>
 

Oracle11gR2--SEC_CASE_SENSITIVE_LOGON參數解析