修改密码必须用sys或system用户
//----修改用户密码------//
ALTER USER SYSTEM IDENTIFIED BY MANAGER
alter user system identified by manager
//----解锁scott账户-----//
1.ALTER USER SCOTT ACCOUNT UNLOCK
2.alter user scott identified by tiger account unlock ;
//----解锁hr用户----------//
alter user hr identified by hr account unlock
-------连接scott用户---
conn scott/tiger;
-----断开连接---
disconnect;
---再次连接---
conn 用户名/密码
---更改自己用户密码---
passward;
alter user scott identified by 密码
-----查询数据库名-----
select name from v$database;