创建scott用户：

SQL> conn / as sysdba
Connected.
SQL> @%oracle_home%\rdbms\admin\utlsampl.sql
建立完成以后会自动退出sqlplus,请重新登录既可.
运行sqlplus /nolog
SQL> conn scott/tiger

解锁scott用户以及修改其密码：

SQL> conn / as sysdba
Connected.
SQL> alter user scott account unlock identified by tiger;
解锁同时修改密码
User altered.

?