This procedure helped me a bit to manage an Oracle DB's tablespace. I was getting ORA-01653: unable to extend table SYSTEM... errors.
Maybe the following procedure is useful for others as well:
- In order to manage/see the current usage, here's a good script posted by 'bipul' on http://forums.oracle.com/forums/thread.jspa?messageID=3590569
- To check which data files are used:
select name from v$datafile
- To increase that setting: