Oracle忘记用户名和密码

Microsoft Windows [版本 10.0.16299.192]
(c) 2017 Microsoft Corporation。保留所有权利。

C:WINDOWSsystem32>echo %ORACLE_SID%
%ORACLE_SID%

C:WINDOWSsystem32>set ORACLE_SID=fast

C:WINDOWSsystem32>sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on 星期五 2月 2 17:03:37 2018

Copyright (c) 1982, 2014, Oracle. All rights reserved.

连接到:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> alter user fast identified by "fast*123";
alter user fast identified by "fast*123"
*
第 1 行出现错误:
ORA-01918: 用户 'FAST' 不存在

SQL> alter user sys identified by fast*123;
alter user sys identified by fast*123
*
第 1 行出现错误:
ORA-00922: 选项缺失或无效

SQL> alter user sys identified by fast*123;
alter user sys identified by fast*123
*
第 1 行出现错误:
ORA-00922: 选项缺失或无效

SQL> alter user sys identified by "fast*123";

用户已更改。

SQL> alter user system identified by "manager";

用户已更改。

SQL> create user fast identified by "fast*123";
create user fast identified by "fast*123"
*
第 1 行出现错误:
ORA-65096: 公用用户名或角色名无效

SQL> create user "c##fast" identified by "fast*123";

用户已创建。

SQL> grant connect,resource,dba to "c##fast"
2
SQL> grant connect,resource,dba to "c##fast";

授权成功。

SQL> commit;

提交完成。

SQL>

用户名不需要使用双引号======用户名不需要使用双引号

===========================================

SQL> create user c##fast identified by "fast*123";

SQL> grant connect,resource,dba to c##fast;

SQL> alter user c##fast identified by "fast*123";