关于密码重用参数PASSWORD_REUSE_TIME,PASSWORD_REUSE_MAX之间的关系及其演示

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转自：

https://blog.51cto.com/carefree/1382811

测试环境：10.2.0.2.0
测试用户：SCOTT
测试用的三组密码：oracle1 oracle2 oracle3

PASSWORD_REUSE_TIME和PASSWORD_REUSE_MAX：这两个参数必须互相关联设置，password_reuse_time指定了密码不能重用前的天数，而password_reuse_max则指定了当前密码被重用之前密码改变的次数。

总结两者之间的规律：
(1)PASSWORD_REUSE_MAX，PASSWORD_REUSE_TIME都为UNLIMITED，密码可以随意重用，没有任何限制。
(2)PASSWORD_REUSE_MAX，PASSWORD_REUSE_TIME均为指定值时，必须满足这两者的条件时才可以重用密码。
(3)当PASSWORD_REUSE_MAX，PASSWORD_REUSE_TIME两个有其中一个不为UNLIMITED，则密码永远不能重用。

以下为验证过程：

--确认SCOTT使用的DEFAULT profile SQL> select USERNAME from dba_users where PROFILE='DEFAULT' and USERNAME='SCOTT'; USERNAME ------------------------------ SCOTT

第一种情况，PASSWORD_REUSE_TIME,PASSWORD_REUSE_MAX值均为UNLIMITED

SQL> select profile,limit from dba_profiles where profile='DEFAULT' and resource_name='PASSWORD_REUSE_TIME'; PROFILE LIMIT ------------------------------ ---------------------------------------- DEFAULT UNLIMITED SQL> select profile,limit from dba_profiles where profile='DEFAULT' and resource_name='PASSWORD_REUSE_MAX'; PROFILE LIMIT ------------------------------ ---------------------------------------- DEFAULT UNLIMITED --测试 SQL> alter user scott identified by oracle; User altered. SQL> / User altered. SQL> / User altered.

可以发现，用户密码可以不受限制的重用

第二种情况，PASSWORD_REUSE_TIME,PASSWORD_REUSE_MAX值均不为UNLIMITED，这里设定ASSWORD_REUSE_TIME 1/1440表示一分钟后可以重用，PASSWORD_REUSE_MAX 1表示密码更新过一次即可重用。

SQL> alter profile DEFAULT limit PASSWORD_REUSE_MAX 1; Profile altered. SQL> alter profile DEFAULT limit PASSWORD_REUSE_TIME 1/1440; Profile altered. --测试 SQL> alter user scott identified by oracle1; User altered. SQL> select to_char(sysdate,'yyyy-mm-dd,hh24:mi:ss') as a from dual; A ------------------- 2014-03-20,23:40:45 SQL> alter user scott identified by oracle; User altered. SQL> select to_char(sysdate,'yyyy-mm-dd,hh24:mi:ss') as a from dual; A ------------------- 2014-03-20,23:42:05 SQL> alter user scott identified by oracle1; User altered. SQL> select to_char(sysdate,'yyyy-mm-dd,hh24:mi:ss') as a from dual; A ------------------- 2014-03-20,23:42:18 --间隔不足一分钟，更改提示失败 SQL> alter user scott identified by oracle; alter user scott identified by oracle * ERROR at line 1: ORA-28007: the password cannot be reused --直接用上一次的密码更改，更改失败 SQL> alter user scott identified by oracle1; alter user scott identified by oracle1 * ERROR at line 1: ORA-28007: the password cannot be reused

由上面的实验，我们可以看出，PASSWORD_REUSE_TIME,PASSWORD_REUSE_MAX值均不为UNLIMITED，必须同时满足这两个条件才可以更改密码。

第三种情况，PASSWORD_REUSE_TIME 为UNLIMITED，PASSWORD_REUSE_MAX为1

SQL> alter profile DEFAULT limit PASSWORD_REUSE_TIME unlimited; Profile altered. --测试 SQL> alter user scott identified by oracle1; alter user scott identified by oracle1 * ERROR at line 1: ORA-28007: the password cannot be reused SQL> alter user scott identified by oracle2; User altered. SQL> alter user scott identified by oracle1; alter user scott identified by oracle1 * ERROR at line 1: ORA-28007: the password cannot be reused SQL> alter user scott identified by oracle; alter user scott identified by oracle * ERROR at line 1: ORA-28007: the password cannot be reused

由此可以看出，当PASSWORD_REUSE_TIME 为UNLIMITED，PASSWORD_REUSE_MAX为指定值，密码在任何时候都不可以重用。

第四种情况，PASSWORD_REUSE_MAX 为UNLIMITED，PASSWORD_REUSE_TIME为1/1440。

SQL> alter profile DEFAULT limit PASSWORD_REUSE_MAX unlimited; Profile altered. SQL> alter profile DEFAULT limit PASSWORD_REUSE_TIME 1/1440; Profile altered. SQL> select to_char(sysdate,'yyyy-mm-dd,hh24:mi:ss') as a from dual; A ------------------- 2014-03-20,23:50:16 SQL> select to_char(sysdate,'yyyy-mm-dd,hh24:mi:ss') as a from dual; A ------------------- 2014-03-20,23:53:10 SQL> alter user scott identified by oracle2; alter user scott identified by oracle2 * ERROR at line 1: ORA-28007: the password cannot be reused SQL> alter user scott identified by oracle1; alter user scott identified by oracle1 * ERROR at line 1: ORA-28007: the password cannot be reused SQL> alter user scott identified by oracle; alter user scott identified by oracle * ERROR at line 1: ORA-28007: the password cannot be reused SQL> alter user scott identified by oracle4; User altered. SQL> alter user scott identified by oracle; alter user scott identified by oracle * ERROR at line 1: ORA-28007: the password cannot be reused