很多DBA一定对rm -rf深恶痛绝吧，没准哪天自己一个犯迷糊就把数据库给消灭了，然后，就没有然后了……那万一……真的发生了这样的不幸，是否真的就无药可救了吗？未必，还是有解决方法的，也许某天当你不幸遇到，就可以用来救自己了。这里做恢复操作的前提是没有可用的rman备份，或者数据库冷备份等，也就是说，没有任何备份。
一、登陆SQLPLUS，并启动数据库
[Oracle@ora10g ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Aug 25 12:37:50 2014
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to an idle instance.
SQL> startup
ORACLE instance started.
Total System Global Area 285212672 bytes
Fixed Size 1218992 bytes
Variable Size 96470608 bytes
Database Buffers 184549376 bytes
Redo Buffers 2973696 bytes
Database mounted.
Database opened.
--查看实例初始化状态
SQL> select status from v$instance;
STATUS
------------
OPEN
--查看实例名
SQL> show parameter name;
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
db_file_name_convert string
db_name string ora10g
db_unique_name string ora10g
global_names boolean FALSE
instance_name string ora10g
lock_name_space string
log_file_name_convert string
service_names string ora10g
SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
二、模拟rm -rf误操作
[oracle@ora10g ~]$ cd /u01/app/oracle/oradata
[oracle@ora10g oradata]$ ll
total 4
drwxr-x--- 2 oracle oinstall 4096 Aug 25 11:15 ora10g
[oracle@ora10g oradata]$ pwd
/u01/app/oracle/oradata
[oracle@ora10g oradata]$ rm -rf ora10g
[oracle@ora10g oradata]$ exit
logout
[root@ora10g ~]# su - oracle
[oracle@ora10g ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Mon Aug 25 12:43:58 2014
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> select count(*) from dba_objects;
select count(*) from dba_objects
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01116: error in opening database file 1
ORA-01110: data file 1: '/u01/app/oracle/oradata/ora10g/system01.dbf'
ORA-27041: unable to open file
Linux Error: 2: No such file or directory
Additional information: 3
SQL> select count(*) from dba_segments;
select count(*) from dba_segments
*
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-01116: error in opening database file 1
ORA-01110: data file 1: '/u01/app/oracle/oradata/ora10g/system01.dbf'
ORA-27041: unable to open file
Linux Error: 2: No such file or directory
Additional information: 3
由于数据文件都被删除，其中包括system01.dbf，是存放数据字典的容器，想要再访问数据字典中得视图，当然是不可能的了，所以这里会报错，找不到文件，故障出现