[ac]

> but it [acid-state] also limits the points of entry into 1 (which means no outside queries/reports which SQL does very well). > [...] > If you can live with the fact that your application is the only entry point for your data, definitely look into AcidState.

Sorry for the double post, but I couldn't edit my previous reply anymore. You do have a point about SQL being more amenable to outside queries and reports, especially ad-hoc ones. However, take a look at Data.Acid.Remote (http://hackage.haskell.org/packages/archive/acid-state/0.8.2...) which allows you to connect to an acid store in your running application remotely: however, at this time you will have to provide your own security solution for that. Also, for ad-hoc queries to your data you can, probably, bolt on a dynamic Haskell evaluator/interpreter to your application: see http://www.haskell.org/haskellwiki/Safely_running_untrusted_... for a possible solution. That is, of course, not safe (as in Haskell-safe, see the section about exploits), but neither are ad-hoc SQL queries on your live data store.