I keep going into details, thank you for responding. Of the 13 million property assertions, almost 80% are assertions of object properties, ie relationships between individuals. In the last ontology I generated automatically, only for one of the municipalities in Cuba, I had 27 763 887 of object properties assertions, 105 054 data property assertions and 8 158 individuals.
The inference I need is basically the following: 1) To know all the individuals that belong to a class directly and indirectly, taking into consideration the equivalence between classes and between individuals. 2) Given an individual (Ind) and an object property (OP), know all individuals related to "Ind", through OP. Considering the following characteristics of OP: symmetry, functional, transitivity, inverse, equivalence. 3) Search the direct and indirect subclasses of a class. 4) Identify all classes equivalent to a class, considering that the equivalence relation is transitive. 5) Identify the set of superclasses of a class. Could JENA and TDB afford that kind of inference on my big ontologies? Excuse me, but I'm not a deep connoisseur of the SPARQL language. I have only used it to access data that is explicit on the ontology, similar to SQL in relational databases, I have never used it (nor do I know if it is possible to do so) to infer implicit knowledge. I put copy to Ignazio Palmisano, an excellent researcher and connoisseur of the framework OWLAPI. With which I have been exchanging on this subject. Best regards. ----- Mensaje original ----- De: "Dave Reynolds" <dave.e.reyno...@gmail.com> Para: users@jena.apache.org Enviados: Domingo, 19 de Marzo 2017 13:45:48 Asunto: Re: [MASSMAIL]Re: about TDB JENA 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 La @universidad_uci es Fidel. Los jóvenes no fallaremos. #HastaSiempreComandante #HastalaVictoriaSiempre
