SQL*Plus: Release 11.2.0.1.0 Production on Mon Feb 18 15:42:14 2013
OS:Linux node 2.6.32-200.13.1.el5uek #1 SMP Wed Jul 27 21:02:33 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
由于应用的需要，某些用户密码不能过期，需要将密码置成永不过期。下面进行这个实验：
SQL> create user test identified by test;
User created.
SQL> select username,account_status,expiry_date,profile from dba_users where username='TEST';
USERNAME ACCOUNT_STATUS EXPIRY_DA PROFILE
------------------------------ -------------------------------- --------- ------------------------------
TEST OPEN 17-AUG-13 DEFAULT
SQL> select sysdate from dual;
SYSDATE
---------
18-FEB-13
可以看出用户密码有效期为6个月。
控制用户密码有效期限的参数为password_life_time，此参数不能通过show parameter 来查看，它在user的profile中，默认创建用户时profile为default，我们可以查看一下default profile中都控制哪些参数：
SQL> select * from dba_profiles where profile='DEFAULT';
PROFILE RESOURCE_NAME RESOURCE LIMIT
------------------------------ -------------------------------- -------- ----------------------------------------
DEFAULT COMPOSITE_LIMIT KERNEL UNLIMITED
DEFAULT SESSIONS_PER_USER KERNEL UNLIMITED
DEFAULT CPU_PER_SESSION KERNEL UNLIMITED
DEFAULT CPU_PER_CALL KERNEL UNLIMITED
DEFAULT LOGICAL_READS_PER_SESSION KERNEL UNLIMITED
DEFAULT LOGICAL_READS_PER_CALL KERNEL UNLIMITED
DEFAULT IDLE_TIME KERNEL UNLIMITED
DEFAULT CONNECT_TIME KERNEL UNLIMITED
DEFAULT PRIVATE_SGA KERNEL UNLIMITED
DEFAULT FAILED_LOGIN_ATTEMPTS PASSWORD 10
DEFAULT PASSWORD_LIFE_TIME PASSWORD 180
PROFILE RESOURCE_NAME RESOURCE LIMIT
------------------------------ -------------------------------- -------- ----------------------------------------
DEFAULT PASSWORD_REUSE_TIME PASSWORD UNLIMITED
DEFAULT PASSWORD_REUSE_MAX PASSWORD UNLIMITED
DEFAULT PASSWORD_VERIFY_FUNCTION PASSWORD NULL
DEFAULT PASSWORD_LOCK_TIME PASSWORD 1
DEFAULT PASSWORD_GRACE_TIME PASSWORD 7
16 rows selected.
可以看到password_life_time参数就在里面，而且值为180，单位天。