i am wondering how to effectively use the functionality that comes with the object oriented approach such as inheritance

Reading the manual would seem a good starting point.

i was wondering if anyone has hints on how to use that functionality from the perl side... for example with Class::DBI..

Class::DBI is neutral as to the way the database represents tables, so you'd just reference the tables in the same way as normal. Whether Class::DBI is an appropriate base for your database work depends on the application.