Aside from the work on probabilistic inference, there is also many papers on "probabilistic databases" in the last 10 years (Chris did his PhD on that topic). That work has looked at SQL-style query processing over "uncertain"/"probabilistic" data.

These were some of the major projects: https://homes.cs.washington.edu/~suciu/project-mystiq.html, http://maybms.sourceforge.net/, http://infolab.stanford.edu/trio/, http://www.cs.umd.edu/~amol/PrDB/, http://dl.acm.org/citation.cfm?id=1376686.