Just a side note; Jena offers SPARQL 1.1, which includes property paths [1]. In some situations, they can be used to do some forms of inference (e.g. some kinds of problems involving subsumption) right in your SPARQL queries.
--- A. Soroka The University of Virginia Library [1] https://www.w3.org/TR/sparql11-query/#propertypaths > On Mar 19, 2017, at 2:45 PM, Dave Reynolds <dave.e.reyno...@gmail.com> wrote: > > On 19/03/17 15:52, Manuel Enrique Puebla Martinez wrote: >> >> I consider that I did not know how to explain correctly in my previous >> email, I repeat the two questions: >> >> >> 1) I read the page https://jena.apache.org/documentation/tdb/assembler.html, >> I do not think it is what I need. >> >> I work with large OWL2 ontologies from the OWLAPI framework, generated >> automatically. With thousands of individuals and more than 13 million >> property assertions (data and objects). As one may assume, one of the >> limitations I have is that OWLAPI itself can not manage these large >> ontologies, that is, because OWLAPI loads the whole owl file into RAM. Not >> to dream that some classical reasoner (Pellet, Hermit, etc.) can infer new >> knowledge about these great ontologies. >> >> Once explained the problem I have, comes the question: Does JENA solve this >> test ?, ie with JENA and TDB I can generate my great ontologies in OWL2 ?, >> With JENA and TDB I can use a reasoner to infer new implicit knowledge >> (unstated) on my big ontologies? >> >> I do not think JENA will be able to solve this problem, it would be a >> pleasant surprise for me. Unfortunately so far I had not read about TDB and >> the potentialities of JENA in external memory. > > Indeed Jena does not offer fully scalable reasoning, all inference is done in > memory. > > That said 13 million assertions is not *that* enormous, the cost of inference > depends on the complexity of the ontology as much its scale. So 13m triples > with some simple domain/range inferences might work in memory. > > TDB storage itself scales just fine and querying does not load all the data > into memory. So if you don't actually need inference, or only need simple > inference that can be usefully expressed as part of the SPARQL query then you > are fine. > > Dave >
