转自：http://blog.csdn.net/skylinethj/article/details/7892054
单位要将旧数据服务器的数据库迁移到新的服务器上，新服务器连接存储，在处理表空间的过程中不小心将新服务器上/oracle目录下的u01文件夹删除，于是删除表空间时出现问题，现在就演示一下如何解决这个问题
环境：10gR2
[oracle@db1 ~]$ sqlplus / as sysdba
SQL*Plus: Release 10.2.0.1.0 - Production on Wed Dec 21 11:31:18 2011
Copyright (c) 1982, 2005, Oracle. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, OLAP and Data Mining options
SQL>
1.查看数据文件：
SQL> select name from v$datafile;
NAME
--------------------------------------------------------------------------------
+DATA/orcl/system01.dbf
+DATA/orcl/undotbs01.dbf
+DATA/orcl/sysaux01.dbf
+DATA/orcl/users01.dbf
+DATA/orcl/undotbs02.dbf
/oracle/u01/app/oracle/oradata/orcl/SMS.dbf
/oracle/u01/app/oracle/oradata/orcl/WEBDB.dbf
2.查看数据文件状态
SQL> select file#,status,name from v$datafile where name like '%SMS%';
FILE# STATUS
---------- -------
NAME
--------------------------------------------------------------------------------
6 ONLINE
/oracle/u01/app/oracle/oradata/orcl/SMS.dbf
1 rows selected.
3.确认操作系统上SMS数据文件已经不存在，u01文件夹都没有
[oracle@db1 ~]$ ll /oracle/
总计 6778872
drwxr-xr-x 2 oracle oinstall 4096 12-16 17:07 bak
-rw-rw-r-- 1 oracle oinstall 170 12-19 15:41 IMPORT.LOG
4.此时查看数据文件状态，状态没有异常
sec@ora10g> select file#,status,name from v$datafile where name like '%SMS%';
FILE# STATUS NAME
---------- ------- ------------------------------------------------------------
6 ONLINE /oracle/u01/app/oracle/oradata/orcl/SMS.dbf
5.手工将误删除的文件offline drop，成功
SQL> alter database datafile '/oracle/u01/app/oracle/oradata/orcl/SMS.dbf' offline drop;
Database altered.
6.此时，该文件的状态为“RECOVER”
SQL> select file#,status,name from v$datafile where name like '%SMS%';
FILE# STATUS NAME
---------- ------- ------------------------------------------------------------
6 RECOVER /oracle/u01/app/oracle/oradata/orcl/SMS.dbf
7.演示删除表空间，成功。
SQL> alter database datafile '/oracle/u01/app/oracle/oradata/orcl/SMS.dbf' offline drop;
Database altered.
8.最后确认，删除得很彻底。
SQL>select file#,status,name from v$datafile where name like '%SMS%';
no rows selected
SQL> select name from v$datafile;
NAME
--------------------------------------------------------------------------------
+DATA/orcl/system01.dbf
+DATA/orcl/undotbs01.dbf
+DATA/orcl/sysaux01.dbf
+DATA/orcl/users01.dbf
+DATA/orcl/undotbs02.dbf
/oracle/u01/app/oracle/oradata/orcl/WEBDB.dbf