背景：undo表空间如果属性是自动增长的，从而表空间过大，那么就重新创建一个新的UNDO表空间。

思路：

1：查看当前UNDO表空间

2：查看数据文件创建地方

3：创建UNDO表空间

4：切换undo表空间

5：将原来的UNDO表空间OFFLINE

6：drop 原来表空间。

SQL> select name from v$datafile;

NAME
--------------------------------------------------------------------------------
E:ORACLEPRODUCT10.2.0ORADATAFOCUSSYSTEM01.DBF
E:ORACLEPRODUCT10.2.0ORADATAFOCUSUNDOTBS01.DBF
E:ORACLEPRODUCT10.2.0ORADATAFOCUSSYSAUX01.DBF
E:ORACLEPRODUCT10.2.0ORADATAFOCUSUSERS01.DBF
E:ORACLEPRODUCT10.2.0ORADATAFOCUSAZ_SALES_FOCUS_TS01.DBF

SQL> create undo tablepsace undotbs2 datafile
2 'E:ORACLEPRODUCT10.2.0ORADATAFOCUSUNDOTBS02.DBF' size 100m;

create undo tablepsace undotbs2 datafile
'E:ORACLEPRODUCT10.2.0ORADATAFOCUSUNDOTBS02.DBF' size 100m

ORA-00901: ÎÞЧ CREATE ÃüÁî

SQL> create undo tablespace undotbs2 datafile
2 'E:ORACLEPRODUCT10.2.0ORADATAFOCUSUNDOTBS02.DBF' size 100m;

Tablespace created

SQL> alter system set undo_tablespace=undotbs2;

System altered

SQL> show parameter undo_tablespace;

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
undo_tablespace string UNDOTBS2

SQL> alter tablespace undotbs1 offline;

Tablespace altered

SQL> drop tablesapce undotbs1;

drop tablesapce undotbs1

ORA-00950: ÎÞЧ DROP Ñ¡Ïî

SQL> drop tablespace undotbs1;

Tablespace dropped

[@more@]