C:\Documents and Settings\gqgai>sqlplus "/ as sysdba"

SQL*Plus: Release 9.2.0.6.0 - Production on Fri Mar 4 20:55:59 2005

Copyright (c) 1982, 2002, Oracle Corporation.  All rights reserved.


Connected to:
Oracle9i Enterprise Edition Release 9.2.0.6.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.6.0 - Production

20:55:59 SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
20:56:14 SQL> startup
ORACLE instance started.

Total System Global Area   59842188 bytes
Fixed Size                   454284 bytes
Variable Size              33554432 bytes
Database Buffers           25165824 bytes
Redo Buffers                 667648 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 2 - see DBWR trace file
ORA-01110: data file 2: 'D:\ORADATA\EYGLE\UNDOTBS01.DBF'


20:59:28 SQL> alter database datafile 'D:\ORADATA\EYGLE\UNDOTBS01.DBF'
              offline drop;

Database altered.

Elapsed: 00:00:00.00
20:59:34 SQL> alter database open;

Database altered.

Elapsed: 00:00:02.04
20:59:40 SQL> select name from v$datafile;

NAME
-------------------------------------------------------
D:\ORADATA\EYGLE\SYSTEM01.DBF
D:\ORADATA\EYGLE\UNDOTBS01.DBF
D:\ORADATA\EYGLE\PERFSTAT01.DBF
D:\ORADATA\EYGLE\EYGLE.DBF

21:00:55 SQL> create undo tablespace undotbs2
21:01:03   2  datafile 'd:\oradata\eygle\undotbs2.dbf' size 10M;

Tablespace created.

Elapsed: 00:00:02.02

21:06:29 SQL> ALTER SYSTEM SET undo_tablespace='UNDOTBS2' ;

System altered.

Elapsed: 00:00:00.01

3.删除原来的undo表空间
drop tablespace UNDOTBS1 including contents;
4.可以将undo表空间设置为自动扩展模式
ALTER DATABASE 
DATAFILE 'D:\Oracle\oradata\CMO_L\UNDOTBS2.ora' AUTOEXTEND 
ON NEXT  1024K