DCNM 7.2.3 with Oracle 11g Express

We have a small environment originally with DCNM 6.2.3 and Postgres 8.3.  We have trouble installing and upgrading existing Postgres.  Most likely it is caused by modified dll permission etc based on forum.  So, we do a fresh install with DCNM 7.2.3 with Oracle 11g Express on a Windows 2008 R2 box.  For Postgres, we can run purge to remove old / historical records in the database to reduce the size.  For Oracle Express 11g, do I need to do the same?