Ever heard of object databases?
These are able to model the world much better than
"classical" databases. We are now trying some
experiments on top of Quiper DB (Quiper DB is a
relational/hierarchical data store; see quiper
project in FM or quiper.zapwerk.com) for binding
it to Java and store Java objects directly in DB
(including references between objects). Side
effect is that no structure infos are necessary
and one can later change Java classes to contain
more fields without ever thinking about
restructuring the database.
However, this poses some additional problems, like
garbage collection of unused objects and the like.