sqlplus / as sysdba

登录数据库以最高权限登录

SQL*Plus: Release 11.2.0.1.0 Production on Thu Apr 11 09:00:05 2019

Copyright (c) 1982, 2009, Oracle. All rights reserved.

Connected to an idle instance.

SQL> show user;

产看当前登录用户

USER is "SYS"

SQL> startup

启动数据库

ORACLE instance started.

Total System Global Area 784998400 bytes

Fixed Size 2217464 bytes

Variable Size 482347528 bytes

Database Buffers 293601280 bytes

Redo Buffers 6832128 bytes

Database mounted.

Database opened.

SQL> select username, account_status from dba_users order by username;

查看OracleDBA_USER视图
DBA_USERS视图中ACCOUNT_STATUS记录的用户的当前状态，一般情况下在使用的正常用户均处于OPEN状态。
例如我们查看sec用户的当前状态，此时该用户处于OPEN状态，可以正常使用。

USERNAME ACCOUNT_STATUS 状态
ANONYMOUS EXPIRED & LOCKED 此时状态为过期并且锁住
APEX_030200 EXPIRED & LOCKED
APEX_PUBLIC_USER EXPIRED & LOCKED
APPQOSSYS EXPIRED & LOCKED
BI EXPIRED & LOCKED
CTXSYS EXPIRED & LOCKED
DBSNMP OPEN 开放的
DIP EXPIRED & LOCKED
EXFSYS EXPIRED & LOCKED
FLOWS_FILES EXPIRED & LOCKED
HR EXPIRED 过期的
IX EXPIRED & LOCKED
MDDATA EXPIRED & LOCKED
MDSYS EXPIRED & LOCKED
MGMT_VIEW OPEN
OE EXPIRED & LOCKED
OLAPSYS EXPIRED & LOCKED
ORACLE_OCM EXPIRED & LOCKED
ORDDATA EXPIRED & LOCKED
ORDPLUGINS EXPIRED & LOCKED
ORDSYS EXPIRED & LOCKED
OUTLN EXPIRED & LOCKED
OWBSYS EXPIRED & LOCKED
OWBSYS_AUDIT EXPIRED & LOCKED
PM EXPIRED & LOCKED
SCOTT OPEN
SH EXPIRED & LOCKED
SI_INFORMTN_SCHEMA EXPIRED & LOCKED
SPATIAL_CSW_ADMIN_USR EXPIRED & LOCKED
SPATIAL_WFS_ADMIN_USR EXPIRED & LOCKED
SYS OPEN
SYSMAN OPEN
SYSTEM OPEN
WMSYS EXPIRED & LOCKED
XDB EXPIRED & LOCKED
XS$NULL EXPIRED & LOCKED

SQL> alter user hr account unlock;

更改用户hr帐户为未锁

SQL> alter user hr identified by hr;

更改用户hr密码为hr

SQL> conn hr /hr

切换用为hr/密码为hr

Connected.

SQL> show user

查看当前登录账号

USER is "HR"

SQL>