in that case, you need some inference at one time or another. two strategies: Strat 1: materialize the infered triples[1], inject in the DB, and then query with the regular SPARQL engine (:ok for very small datasets, and slow-changing data). for reasonably big data, you can use the OWL2-RL subset of OWL2. as far as i know, an implementation of OWL2-RL exists with drools, and you can play with it in protege or eulerGUI. Strat 2: rewrite the query according to the data structure and run on your existing dataset (:the current trade off for big data on top of OWL). for that, you must use the OWL2-QL subset of OWL2. DBs such as stardog or OWLIM handle such query rewriting, i do not know if fuseki has such a query rewriter.
as far as i understand, this is the global picture of OWL2+RDF. i let the local gurus correct the above statements. [1]: in our example, one infered tripe would be :DATA rdf:type :C On Thu, May 23, 2013 at 1:53 AM, Bahador(reza)? OFOGHI <[email protected]>wrote: > Yes, I would like to retrieve :DATA since in myOntology, there is this > subClassOf relationship that can be traveresed by the reasoner. > > thanks. > BO > > > ________________________________ > From: Olivier Rossel <[email protected]> > To: [email protected]; Bahador(reza)? OFOGHI <[email protected]> > Sent: Wednesday, 22 May 2013 6:54 PM > Subject: Re: Owl Ontology and TDB Individuals > > > Let's take an example to clarify. > > myOntology.owl: > :SC rdfs:subClassOf :C > > myData.rdf: > :DATA rdf:type :SC > > You want to retrieve all resources of type :C > So you craft a SPARQL query for that: > SELECT * WHERE {?s rdf:type :C} > > Do you expect such a query to return :DATA, or not? > > > On Wed, May 22, 2013 at 12:47 AM, Bahador(reza)? OFOGHI < > [email protected] > > wrote: > > > Inference would be on concepts and based on the relationships between > > them. Data will then be fecthed accordingly since they are instances of > the > > concepts, isn't it? I am not aware of whether it is generally possible to > > do inference on data. > > > > > > Bahador(reza)? OFOGHI, PhD > > Major: Information Technology > > > > > > > > ________________________________ > > From: Olivier Rossel <[email protected]> > > To: [email protected]; Bahador(reza)? OFOGHI <[email protected]> > > Sent: Tuesday, 21 May 2013 10:16 PM > > Subject: Re: Owl Ontology and TDB Individuals > > > > > > Is it inference on data themselves? Or on concepts only? > > > > > > On Tue, May 21, 2013 at 11:54 AM, Bahador(reza)? OFOGHI < > > [email protected] > > > wrote: > > > > > Thanks Olivier, > > > > > > In fact, I do need to make use of inference in the OWL ontology. This > is > > a > > > big ontology (being merged with some other ontologies) only one part of > > > which is the names I have described. In this case, would you/anyone > else > > > have any ideas how I might be able to get this done. > > > > > > thanks again > > > Bahador > > > > > > > > > > > > ________________________________ > > > From: Olivier Rossel <[email protected]> > > > To: [email protected]; Bahador(reza)? OFOGHI <[email protected]> > > > Sent: Tuesday, 21 May 2013 7:42 PM > > > Subject: Re: Owl Ontology and TDB Individuals > > > > > > > > > Basically, you do not have to load both the OWL and the RDF in the DB. > > > Such a RDF: > > > :nameNumberOne a :NAME. > > > :nameNumberOne :has_a :namePartNumberOne . > > > :nameNumberOne :has_a :namePartNumberTwo . > > > > > > will load just fine in Fuseki. > > > You can then query it without having to load the OWL in the DB. > > > (RDF databases are mostly schemaless). > > > > > > The OWL is here just to be understood by the domain expert who > > > creates the query. > > > > > > (Note: in an inference-aware DB, it *is* interesting to load both the > OWL > > > and the RDF together, but I do not think you have the need for > > inference). > > > > > > > > > On Tue, May 21, 2013 at 3:22 AM, Bahador(reza)? OFOGHI > > > <[email protected]>wrote: > > > > > > > THanks Andy and David, > > > > > > > > I have now looked at this and I still have questions! > > > > > > > > 1- when you say transactions will not work across a mixture of graphs > > in > > > a > > > > dataset, does that mean that I will not be able to query and/or use > > > > reasoners on this dataset? > > > > 2- if not, then what would be the best solution to keep an RDF/XML > > > > ontology which will have thousands of individuals? I would have > > thought I > > > > could create the structure ontology (the OWL file) and keep it > separate > > > > from the data file (as in TDB) that will be assigned to the OWL > > ontology > > > > nodes. I am new to this field and I appreciate any hints. > > > > > > > > To make it more clear or refresh your memory, here is the problem I > am > > > > trying to solve: > > > > > > > > I have created an ontology in OWL somewhere in which I have a node > > named > > > > NAME which includes subparts of the name in NAME_PART1, ..., > > NAME_PARTn. > > > I > > > > have a large CSV data file that has (many) records of names and the n > > > name > > > > parts. I will have to convert the CSV file into an RDF dataset > (which I > > > > will find a way for, should not be too complicated). Then, I need to > > > make a > > > > connection between the RDF dataset of these records and the OWL > > ontology > > > > that keeps the relationships between the concept nodes, e.g., NAME > > has_a > > > > NAME_PART1. > > > > > > > > Given that I have the two OWL and RDF files ready, what would I have > to > > > do > > > > next to be able to query over the NAMEs and NAME_PARTs. What does it > > take > > > > to glue the two files? > > > > > > > > kind regards, > > > > Bahador > > > > > > > > > > > > > > > > ________________________________ > > > > From: David Jordan <[email protected]> > > > > To: "[email protected]" <[email protected]> > > > > Sent: Thursday, 16 May 2013 5:13 AM > > > > Subject: RE: Owl Ontology and TDB Individuals > > > > > > > > > > > > OK, now with your clarification it makes sense to me and is what I > > > > expected. > > > > > > > > > > > > -----Original Message----- > > > > From: Andy Seaborne [mailto:[email protected]] > > > > Sent: Wednesday, May 15, 2013 3:03 PM > > > > To: [email protected] > > > > Subject: Re: Owl Ontology and TDB Individuals > > > > > > > > On 15/05/13 18:47, David Jordan wrote: > > > > > Andy, Please clarify something. In this reply, you state * Put the > > > > > ontology in one named graph and the individuals in another one, or > > the > > > > > default graph, and hence in the same database? * You can put a > single > > > > > graph from TDB into a general dataset or just work with that one > > graph > > > > > (transactions will not work across a mixture of graphs in a > dataset). > > > > > > > > > > You then reference the online docs that state: It is possible to > use > > > > > just one of the graphs from the dataset. A common way of working > with > > > > > one graph is to use the default graph of the dataset. > > > > > > > > > > > > Dataset dataset = DatasetFactory.createMem() ; > > > > Dataset tdb = TDBFactory.createDataset() ; > > > > > > > > // Pick one graph/model out of the dataset. > > > > Model m1 = tdb.getNamedModel("http://example/tdb/graph";) ; > > > > dataset.addNamedModel("http://example/individuals";, m1) ; > > > > > > > > // A model with completely different storage > > > > Model m2 = ModelFactory.createDefaultModel() ; > > > > dataset.addNamedModel("http://example/ontology";, m2) ; > > > > > > > > ... a dataset with a mix of model storage implementations. > > > > > > > > > > > > > > My code uses the interface com.hp.hpl.jena.query.Dataset. It allows > > me > > > > > to start/stop transactions and to access named models. I can access > > > > > multiple named models. Isn't a model a graph in the database? > > > > > Isn't a graph == model == graph ? You say that "transactions will > not > > > > > work across a mixture of graphs in a dataset". So a given > > > > > com.hp.hpl.jena.query.Dataset object, while it can return multiple > > > > > named Models, you cannot use them in the same transaction? > > > > > > > > then > > > > > > > > dataset.begin(ReadWrite.READ) ; > > > > > > > > ==> exception. "Transactions not supported" > > > > > > > > > When you said "a general dataset", are you referring to the default > > > > > model/graph, which is stored in a triple table in SDB and > essentially > > > > > is using the single default graph managed by TDB/SDB? > > > > > > > > The kind of dataset returned by DatasetFactory.createMem() > > > > > > > > > Some of the wording used, both in the documentation and in your > > reply, > > > > > seem vague to me, with multiple interpretations. I don't believe > the > > > > > single sentence "It is possible to use just one of the graphs from > > the > > > > > dataset." is true. > > > > > > > > Could you suggest improvements? > > > > > > > > Andy > > > > > > > > > >
