The network's patents are available royalty-free to any party that agrees not to file infringement suits involving its own patents "against the Linux environment." Under the network's terms, that environment includes not just the kernel at the heart of the open-source operating system, but also higher-level components including the open-source MySQL and PostgreSQL databases that compete with Oracle's own core products.
http://news.com.com/Oracle+bands+with+open-source+patent+group/2100-7344_3-6170717.html

Patent aggregation/pool as a way to stave off competition.