Re: ISSUE-1: Inferencing and current databases

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DBpedia has the advantage that the DBpedia ontology does not have
subproperties of rdfs:subClassOf, which makes subclass inferencing simpler.

SHACL does not (yet) have this feature - users can create constraint graphs
that create subproperties of rdfs:subClassOf and use data graphs that do the


On 05/21/2015 05:36 AM, Dimitris Kontokostas wrote:
> On Mon, Apr 13, 2015 at 10:00 AM, Holger Knublauch
> < <>> wrote:
> In order to make some progress on the question "what inferencing can or 
> must be used", I started a wiki page with links to the reasoning support 
> of various popular RDF/SPARQL databases
> Maybe some more knowledgeable people can provide additional details
> where needed, and add databases that I forgot.
> While many (but not all) database seem to support RDFS, I tried to 
> understand the set up procedures for graph-level inferencing, which are 
> sometimes quite involving (e.g. how to tell the system which class 
> definitions to use for an instances graph). A problem that I see is that 
> once inferencing is activated per graph, it seems to be impossible to 
> distinguish asserted from inferred triples. This means that in a typical 
> scenario for constraint checking, if someone edits an instance on a
> form, the form may also display inferred triples that in fact cannot be
> edited.
> So I have no idea how we could realistically rely on database-level 
> inferencing at this stage.
> I would also like to hear from others, how many people have actually 
> activated any of those inferencing modes in their deployed systems, and 
> what the performance impact is. For example, Dimitris, is the dbpedia
> set up using inferencing?
> I delayed too much the reply on this but it is related to the discussion
> we had yesterday and the action on Arthur & Holger. In DBpedia we perform
> type(-only) inferencing during extraction time. A simplified workflow is:
> using the infobox-to-ontology mappings we assign a type to a resource but
> when we write the type statements we transitively get all super types
> defined in the DBpedia ontology and write the additional type statements.
>  This makes querying or statistics about e.g. dbo:Person(s) or
> dbo:Place(s) much easier and closer to the user expectations. Although
> the DBpedia ontology has rdfs:subPropertyOf relations we do not perform
> similar inferencing on the properties.
> Best, Dimitris
> Thanks, Holger
> -- Dimitris Kontokostas Department of Computer Science, University of
> Leipzig & DBpedia Association Projects:,
> http:// 
> Homepage: Research Group:
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Received on Thursday, 21 May 2015 13:08:05 UTC