[dom0]

> I'm not too familiar with ZODB, but it looks like it tries to impose OO on a database, while in reality relational model works best with data, so making programing language able to interact with data that way would be better.

ZODB itself is essentially a transactional single-object store, where that "single object" is usually the root node of an arbitrary (possibly cyclic) object graph. Storage depends on the backend, nowadays you'd usually use file storage for development and relstorage for any kind of deployment.

It doesn't have any query language, Python is. There are no indices beyond those that you explicitly create (eg. a dictionary would be a simple index, but other packages provide more complex indices, like B-Trees - the nice thing here is that anything that goes into the DB is fully transacted, which removes a lot of headache that you'd have with other solutions (eg. flat XML files)).

ZODB thrives when your data model is too complex to easily or efficiently map into SQL, when you don't do or need efficient complex ad-hoc queries and when 180 % performance and concurrency (although this was recently improved through the MVCC reimplementation) isn't the highest priority. Since it's pretty good at caching (much better than most ORMs) performance usually doesn't suck.