SELECT OBJECT_NAME,OBJECT_TYPE FROM USER_OBJECTS;

（1）conn sys/sys as sysdba; //以DBA的身份登录
（2）alter user scott account unlock;// 然后解锁
（3）conn scott/tiger //修改一下密码就可以了 

SQL>  select sid,serial#,username,status from v$session;SID    SERIAL# USERNAME                       STATUS
---------- ---------- ------------------------------ --------1          1                                ACTIVE2          1                                ACTIVE3          1                                ACTIVE4          1                                ACTIVE5          3                                ACTIVE6          1                                ACTIVE11          7                                ACTIVE63          5                                ACTIVE64          1                                ACTIVE65          1                                ACTIVE66          1                                ACTIVESID    SERIAL# USERNAME                       STATUS
---------- ---------- ------------------------------ --------68          9                                ACTIVE70        178 HR                             INACTIVE125          1                                ACTIVE126          1                                ACTIVE127          1                                ACTIVE128          1                                ACTIVE129          1                                ACTIVE131          7                                ACTIVE133         71 SYS                            ACTIVE187          1                                ACTIVE188          1                                ACTIVESID    SERIAL# USERNAME                       STATUS
---------- ---------- ------------------------------ --------189          1                                ACTIVE190          1                                ACTIVE191         37                                ACTIVE192          7                                ACTIVE194          1                                ACTIVE27 rows selected.

alter system kill session '11,8';

SQL> SELECT * FROM DEPARTMENTS;
SELECT * FROM DEPARTMENTS
*
第 1 行出现错误:
ORA-00028: 您的会话己被终止

SQL> select username,user_id,account_status from dba_users where account_status = 'OPEN' order by 1;USERNAME                          USER_ID ACCOUNT_STATUS
------------------------------ ---------- --------------------------------
A1                                     96 OPEN
A2                                     94 OPEN
A3                                     95 OPEN
ARCER                                  91 OPEN
HR                                     85 OPEN
SYS                                     0 OPEN
SYSTEM                                  5 OPEN
U1                                     92 OPEN
U2                                     93 OPEN9 rows selected.

SQL> select username from v$session where username is not null order by 1;USERNAME
------------------------------
ARCER
SYS
SYS