Add tablespace / datafile

Increase the size of the datafile:

SQL> alter database datafile '/ebiz/oracle/test/db/apps_st/data/system04.dbf' autoextend on maxsize 1G;

SQL> alter database datafile '/ebiz/oracle/test/db/apps_st/data/system04.dbf' resize 3G;

Add an additional datafile:

SQL> alter tablespace system add datafile '/ebiz/oracle/test/db/apps_st/data/system05.dbf' size 2G;