- From: Jim Hendler <hendler@cs.rpi.edu>
- Date: Thu, 6 Mar 2008 19:27:20 -0500
- To: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
Ahh, I misunderstood - I think we need to be very clear on this - I think some of us were assuming that the idea of the DB fragment was to be able to represent something close to a DB schema and use it in processing data from the DB (a la datalog/SQL type stuff) - sort of like expressing an E/R model and then using it to make simple inferences over the data. Anyway, a lot of the project will be correctly describing these fragments and their features. -JH On Mar 6, 2008, at 6:26 PM, Ian Horrocks wrote: > Actually, the primary idea of DL-Lite is that it has logspace data > complexity, which means that query answering can be implemented > using standard (relational) DB technology. In particular, a > conjunctive query against a DL-Lite ontology can be re-written as an > SQL query against a relational DB containing instance data. > > Ian > > > On 6 Mar 2008, at 19:23, Jim Hendler wrote: > >> >> I thought the primary idea of DL-Lite was that it would provide >> primary database functionality -- how can it do that without keys? >> >> >> On Mar 6, 2008, at 6:18 AM, Bijan Parsia wrote: >> >>> >>> On 6 Mar 2008, at 11:04, Ivan Herman wrote: >>> >>>> Boris, Bernardo, >>>> >>>> I went through >>>> >>>> http://www.w3.org/2007/OWL/wiki/Fragments_Proposal >>>> >>>> again today. One thing that I may have missed: I tried to see if >>>> I can use (inverse)functional properties for DL-Lite or not. I >>>> did not find any reference to those neither in 3.1 nor in 3.2. >>>> Again, I may have missed something... >>> >>> Let's see if I can discern from the text the situation. (As a test >>> of the spec.) >>> >>> In section 3: >>> http://www.w3.org/2007/OWL/wiki/Fragments_Proposal#DL-Lite >>> >>> """Several variants of DL-Lite have been described in the >>> literature. The variant presented here is called DL-LiteR since it >>> allows for property inclusion axioms; it therefore contains the >>> intersection between RDFS and OWL 1.1 DL. Other variants trade >>> property inclusion axioms for functionality and inverse- >>> functionality of object properties.""" >>> >>> I think this is clear that functionality and inverse functionality >>> of *object* properties are forbidden. >>> >>> Actually ,the rest of the sections are quiet about data properties >>> altogether. Which would mean that data properties are forbidden in >>> this variant. Which means that it's not really the intersection of >>> RDFS and OWL 1.1 DL? >>> >>> I do think that if we make this DL Lite not have data properties, >>> the text should call that out (e.g., in the list of missing >>> features). OTOH, I think we should allow data properties ;) I >>> would think it would be ok to trade datasubproperties for keys >>> (from a user pov)...I don't know if that would be ok from the >>> logic/impelmentation pov off the top of my had (while retaining >>> object subproperties). >>> >>> Cheers, >>> Bijan. >>> >>> >>> >> >> "If we knew what we were doing, it wouldn't be called research, >> would it?." - Albert Einstein >> >> Prof James Hendler http://www.cs.rpi.edu/~hendler >> Tetherless World Constellation Chair >> Computer Science Dept >> Rensselaer Polytechnic Institute, Troy NY 12180 >> >> >> >> >> > "If we knew what we were doing, it wouldn't be called research, would it?." - Albert Einstein Prof James Hendler http://www.cs.rpi.edu/~hendler Tetherless World Constellation Chair Computer Science Dept Rensselaer Polytechnic Institute, Troy NY 12180
Received on Friday, 7 March 2008 00:27:55 UTC