- From: Gary Hallmark <gary.hallmark@oracle.com>
- Date: Fri, 15 Dec 2006 16:56:02 -0800
- To: W3C RIF WG <public-rif-wg@w3.org>
I haven't heard of anyone seriously wanting a RIF SQL dialect. AFAIK, Oracle is interested in something for interchange of business rules, both PR and ECA. Michael Kifer wrote: >>>This would be a ridiculous and unjustified restriction. >>> >>>The core is for exchange. There is no requirement for any concrete >>>system to properly include the core. (Don't confuse concrete systems with >>>RIF dialects.) >>> >>> >>I'm not sure where the disagreement or misunderstanding here is. >> >>My understanding fits with what Gary said, that RIF Core is a dialect >>and it's a part of every RIF dialect, so every rule engine using RIF >>must implement RIF Core. >> >> > >I think that this requirement makes no sense and, furthermore, is meaningless. >Suppose people want to exchange aggregate-free subsets of SQL 1992 through RIF. >Does it mean that RIF core should be limited to relational algebra? >Or does it mean that we will kick them out even though they can perfectly >use RIF core to exchange their stuff (preserving semantics etc.) we will >somehow stop them until they implement full RIF Core? > >(Note that different SQL vendors have various deviations from SQL 1992 >(even though most of them claim to support it!), so such an exchange is not >completely out of question.) > > --michael > > > >>We'll need some normative Conformance text at some point, something a >>bit like: >> http://www.w3.org/TR/owl-test/#consistencyChecker >> >>We could say something like (as a rought first cut): >> >> A "RIF Core Rule Engine" is a rule engine which can perform sound >> and complete reasoning on any rule set which can encoded in one or >> more RIF Core documents. It must be able to answer all queries >> against the deductive closure of the ruleset, where a query is >> equivalent to a RIF Core anticedent, and to answer a query means to >> provide every matching set of bindings to the variables in the >> anticedent. >> >>At the moment, unless some new information comes along, I'm inclined to >>agree that we need to leave recursive Horn rules out of the core. >> >>My understanding is that recursive Horn rules are also a problem for >>prolog. As with rete systems, there are lots of clever and effective >>ways of dealing with this problem (I was once an enthusiastic XSB user), >>but my sense is that they are still kind of cutting edge instead of the >>kind of dirt simple we want in RIF Core. With non-recursive rules, one >>can do the trivial mapping to prolog or rete rules and any halfway >>decent engine will be a sound and complete reasoner for RIF Core rules. >>I think that's what we want. >> >>We could go another step back for RIF Core, all the way to datalog, but >>I think non-recursive terms are still quite useful (eg for defining >>uncle), so I'd rather not do that. >> >> -- Sandro >> >> >> > > > >
Received on Saturday, 16 December 2006 02:48:57 UTC