Autch...compare Oracle with Access?????
Access is for really small, home/personal databases, with about max of 3 simultanus connections and a max of about 10000 entries.
Oracle (expensive) is meant to deal with huge databases, for hundreds of thousands of users and even more entries. It is more stable etc.
And then: Access is only a database, Oracle a DBMS (Management System) with a lot more functionality.
Hope this helps