Uhoh, someone got the patent on O/R mapping...
http://www.freshpatents.com/Mapping-architecture-for-arbitrary-data-models-dt20050303ptan20050050068.php (via Yves Reynhout)
Too silly for words, if I might add. The patent description is so incredibly vague, almost every piece of software which even smells it would map something seems to fall under this 'invention'. One good example why software patents should never be implemented in Europe.
Edit It seems to be Microsoft who has acquired this patent. Now, if only some old-aged smalltalk / Java guys would step forward and say "Prior Art!"