UNDO Tables Space File deleted accidently

Question

Dear All,
I performed following actions on my Oracle 11g Database under Windows 32-bits OS.
CREATE UNDO TABLESPACE UNDOTBS2 DATAFILE 'C:\app\oradata\ABCD\undotbs2.dbf' SIZE 10 M AUTOEXTEND OFF ;
ALTER SYSTEM SET undo_tablespace = UNDOTBS2;
shutdown immediate
After this when Database went down I deleted UNDOTBS1 datafile from the folder permanently but before that I forget to use the following statement:
DROP TABLESPACE undotbs1 INCLUDING CONTENTS AND DATAFILES;
When I tried to startup the database it successfully started instance and database if mounted but it can not be in OPEN mode. I receive the following error messages can any one help how to receover from this situation where as UNDOTBS2 is now default undo tablespace.
SQL> startup pfile='C:\app\admin\ABCD\pfile\init.ora.027200918250'
ORACLE instance started.
Total System Global Area 313860096 bytes
Fixed Size 1332892 bytes
Variable Size 197134692 bytes
Database Buffers 109051904 bytes
Redo Buffers 6340608 bytes
Database mounted.
ORA-01157: cannot identify/lock data file 3 - see DBWR trace file
ORA-01110: data file 3: 'C:\APP\ORADATA\ABCD\UNDOTBS01.DBF'
Thanks

Answer 1

hi,
alter the undo_management=auto to manual in pfile and start up with that..
it will mount and show error
now alter database datafile 'undo_location' offline drop;
then create
CREATE UNDO TABLESPACE UNDOTBS2 DATAFILE 'C:\app\oradata\ABCD\undotbs2.dbf' SIZE 10 M AUTOEXTEND OFF ;
ALTER SYSTEM SET undo_tablespace = UNDOTBS2;
then alter system undo_management=auto scope=spfile;
noe shutdown and startup the DB..
regards,
Deepak