Help for a newbie in Python and ZODB

[Jean-Louis Nespoulous]

Hello everybody,
I am in charge to develop a system who will analyse a network, type
Three-Tier Architecture. I would like to use ZODB or (exclusive)
PostgreSQL. But I don't know witch one to use? Someone could help me
and tell me what are the differencies between ZODB and PostgreSQL. My
system will be developped in Java. If I use ZODB how I'll make the
transition with Python?
Thank you very much