New MS patent: sounds like PG db rules

Hi all,

Haven't delved into PG's rules system for a long time, but to me, this
newly granted Microsoft patent sounds pretty close:

US Patent 7376668 - Dynamic filtering in a database system
Issued on May 20, 2008
http://www.patentstorm.us/patents/7376668/claims.html

Abstract
"A dynamic filtering module receives a request to perform an operation
on data in the database and a input. The dynamic filtering module
provides as an output a modified request to a data access system. The
modified request can include one or more restrictions added to the
original request pertaining to which data will be accessed as a function
of the input."

Am I wrong in thinking that PG provides prior art here?

Regards and best wishes,

Justin Clift

--
Salasaga - Open Source eLearning IDE
http://www.salasaga.org