注意提示符号
c:\sqlplus /nolog
sqlp\ conn sys/system@oracle10 as sysdba // sys为当前的oracle 用户 system 为该用户密码 oracle10 为SID
# alter user soctt account lock; // 把 scott用户锁定
# alter user scott account unlock; //把scott用户解锁
# alter user scott identified by scott //修改scott用户密码为 scott,scott用户默认密码为 tiger

1 Dos下输入C:\sqlplus /nolog

2 以DBA的身份登录
conn sys/password as sysdba;
3 解锁
alter user scott account unlock;
4 弹出一个修改密码的对话框，修改密码
conn scott/tiger

SQL> conn sys/sys as sysdba;
Connected.
SQL> alter user scott account unlock;
User altered.
SQL> commit;
Commit complete.
SQL> conn scott/tiger//请输入新密码，并确认后OK
Password changed
Connected.