从4个方面实战oracle的密码操作
较好的实践是，oracle的密码操作通过profile来实现，而资源则是通过资源消费组来控制，profile其实是种限制。
通过profile来控制密码的使用，大抵有四：
1） 密码的历史
在这里，有两个参数：password_reuse_time和password_reuse_max，比较好的实践是，这两个参数当关联起来使用。 如：password_reuse_time=30，password_reuse_max=10，
用户可以在30天以后重用该密码，要求密码必须被改变超过10次。
实验： www.2cto.com
会话1：sys
sys@ORCL> create profile p1 limit password_reuse_time 1/1440 password_reuse_max 1;
Profile created.
sys@ORCL> alter user scott profile p1;
User altered.
sys@ORCL> alter user scott password expire;
User altered.
sys@ORCL> alter profile p1 limit password_reuse_time 5/1440 password_reuse_max 1;--5分钟后可重用该密码，但这期间必须要被改成其他密码一次
Profile altered.
sys@ORCL> alter user scott password expire;
www.2cto.com
User altered.
会话2：scott
scott@ORCL> exit;
Disconnected from
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
[oracle@localhost ~]$ sqlplus /nolog
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Sep 3 01:11:09 2012
Copyright (c) 1982, 2005, Oracle. All rights reserved.
idle> conn scott/oracle
ERROR:
ORA-28001: the password has expired
Changing password for scott
New password: --使用原密码，即oracle
Retype new password:
ERROR:
ORA-28007: the password cannot be reused
Password unchanged
idle> conn scott/oracle
ERROR:
ORA-28001: the password has expired
Changing password for scott
New password: --使用新密码，改成think
Retype new password:
Password changed
Connected. www.2cto.com
会话1：sys
sys@ORCL> alter user scott password expire;
User altered.
会话2：scott
scott@ORCL> exit;
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
[oracle@localhost ~]$ sqlplus /nolog
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Sep 3 01:19:04 2012
Copyright (c) 1982, 2005, Oracle. All rights reserved.
idle> conn scott/think
ERROR:
ORA-28001: the password has expired
Changing password for scott
New password: --使用最早的密码，即oracle
Retype new password:
Password changed
Connected.
scott@ORCL>
2） 密码的登入校验
在这方面，也有两个参数:
failed_login_attempts:锁定前允许的最大失败登录次数
password_lock_time:锁定时间
实验：
会话1：sys
sys@ORCL> drop profile p1 cascade;
Profile dropped.
www.2cto.com
sys@ORCL> create profile p1 limit failed_login_attempts 1 password_lock_time 1/1440;--失败一次就被锁，被锁1分钟
Profile created.
sys@ORCL> alter user scott profile p1;
User altered.
会话2：scott
[oracle@localhost ~]$ sqlplus /nolog
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Sep 3 01:42:46 2012
Copyright (c) 1982, 2005, Oracle. All rights reserved.
www.2cto.com
idle> conn scott/think
ERROR:
ORA-01017: invalid username/password; logon denied
idle> conn scott/oracle
ERROR:
ORA-28000: the account is locked
idle> conn scott/or