- From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Date: Thu, 6 Mar 2008 23:26:38 +0000
- To: Jim Hendler <hendler@cs.rpi.edu>
- Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
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 > > > > >
Received on Thursday, 6 March 2008 23:26:50 UTC