Is there an ORM that can support Query Notifications?

Is there an ORM out there which easily supports SQL's query notifications, so that when one client updates some data,开发者_开发百科 other clients are alerted to the fact that their data is now outdated?

Ideally I'd like an ORM which manages object identity itself - that is - it refreshes already loaded objects as opposed to always creating new ones.

Does such a thing exist?

If not - could you recommend a pattern / technique for allowing clients to automatically detect data changes?