On 14/04/16 20:35, Jonathan Camilleri wrote:
What is a unionized graph, is it a graph that joins two data sets which are common in set theory?
Yes. An RDF graph is a set of RDF triples (in the set theoretic sense), a union graph is a union of those triple sets.
Dave
On 28 March 2016 at 19:46, Woodward, Arthur E CTR (US) < [email protected]> wrote:Hello Users, I have been having difficulty finding a solution to the problem of building a modular system for ontological query expansion in Fuseki. My goal is to be able to run a query over a unionized default graph, while maintaining the ability to edit the individual named graphs either from the same dataset or a different dataset. I have tried many variations of the Fuseki assembler, and after combing through the documentation and previous e-mails I believe I have constructed an assembler specification that should be working, but it is not. From an e-mail by Rohana Rajapakse on Jan 24, 2014 1:52 am it was indicated that a structure like the one in my file below should allow for an inference engine to be run over a unionized default graph. Data added via Fuseki GUI:: DID NOT WORK Dataset -- Data Graphs -- default -- (empty, with unionDefaultGraph:true in the Data.ttl and Reasoner.ttl assembler files) Entities -- @prefix ex: <http://example.org/> . @prefix owl: <http://www.w3.org/2002/07/owl#> . @prefix rdf: < http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs: < http://www.w3.org/2000/01/rdf-schema#> . @prefix zoo: <http://example.org/zoo/> . ex:dog1 a ex:animal . ex:cat1 a ex:cat . ex:zoo1 zoo:host ex:cat2 . ex:cat3 owl:sameAs ex:cat2 . Ontology -- @prefix ex: <http://example.org/> . @prefix owl: <http://www.w3.org/2002/07/owl#> . @prefix rdf: < http://www.w3.org/1999/02/22-rdf-syntax-ns#> . @prefix rdfs: < http://www.w3.org/2000/01/rdf-schema#> . @prefix zoo: <http://example.org/zoo/> . ex:cat rdfs:subClassOf ex:animal . zoo:host rdfs:range ex:animal . Dataset -- Reasoner default - (no manually entered data) Query -- Run over the Reasoner Dataset PREFIX ex: <http://example.org/> PREFIX owl: <http://www.w3.org/2002/07/owl#> PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX xsd: <http://www.w3.org/2001/XMLSchema#> PREFIX : <http://localhost:3030/Test/data/> PREFIX http: <http://www.w3.org/2011/http#> SELECT ?animal WHERE { ?animal a ex:animal . } LIMIT 10 0 Results. If the data in the "Data" dataset is moved from the named graphs to the default graph and the unionDefaultGraph:true option is commented out from the Data.ttl file, and the same query above is run, there are 4 results. { "head": { "vars": [ "animal" ] } , "results": { "bindings": [ { "animal": { "type": "uri" , "value": "http://example.org/dog1"; } } , { "animal": { "type": "uri" , "value": "http://example.org/cat1"; } } , { "animal": { "type": "uri" , "value": "http://example.org/cat2"; } } , { "animal": { "type": "uri" , "value": "http://example.org/cat3"; } } ] } } Data.ttl:: 1 @prefix : <http://base/#> . 2 @prefix tdb: <http://jena.hpl.hp.com/2008/tdb#> . 3 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . 4 @prefix ja: <http://jena.hpl.hp.com/2005/11/Assembler#> . 5 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> . 6 @prefix fuseki: <http://jena.apache.org/fuseki#> . 7 8 :service_tdb_all a fuseki:Service ; 9 rdfs:label "TDB Data" ; 10 fuseki:dataset :tdb_dataset_readwrite ; 11 fuseki:name "Data" ; 12 fuseki:serviceQuery "query" , "sparql" ; 13 fuseki:serviceReadGraphStore "get" ; 14 fuseki:serviceReadWriteGraphStore 15 "data" ; 16 fuseki:serviceUpdate "update" ; 17 fuseki:serviceUpload "upload" . 18 19 :tdb_dataset_readwrite 20 a tdb:DatasetTDB ; 21 tdb:location "/home/evan/Documents/apache-jena-fuseki-2.3.1/run/databases/Data" ; 22 tdb:unionDefaultGraph true ; 23 . 24 Reasoner.ttl:: @prefix : <http://base/#> . 2 @prefix tdb: <http://jena.hpl.hp.com/2008/tdb#> . 3 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . 4 @prefix ja: <http://jena.hpl.hp.com/2005/11/Assembler#> . 5 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> . 6 @prefix fuseki: <http://jena.apache.org/fuseki#> . 7 8 :service1 a fuseki:Service ; 9 fuseki:dataset :tdb_dataset_readwrite ; 10 fuseki:name "Reasoner" ; 11 fuseki:serviceQuery "query" , "sparql" ; 12 fuseki:serviceReadGraphStore "get" ; 13 fuseki:serviceReadWriteGraphStore 14 "data" ; 15 fuseki:serviceUpdate "update" ; 16 fuseki:serviceUpload "upload" . 17 18 tdb:GraphTDB rdfs:subClassOf ja:Model . 19 tdb:DatasetTDB rdfs:subClassOf ja:RDFDataset . 20 21 :tdb_dataset_readwrite a ja:RDFDataset ; 22 ja:defaultGraph :model2 ; 23 ja:namedGraph 24 [ ja:graphName "Data" ; 25 ja:graph :graph ] ; 26 . 27 28 :tdb_intermediate_dataset a tdb:DatasetTDB ; 29 tdb:location "/home/evan/Documents/apache-jena-fuseki-2.3.1/run/databases/Data"; 30 tdb:unionDefaultGraph true ; 31 . 32 33 :graph rdf:type tdb:GraphTDB ; 34 tdb:dataset :tdb_intermediate_dataset 35 . 36 37 :model2 a ja:InfModel ; 38 ja:reasoner [ ja:reasonerURL < http://jena.hpl.hp.com/2003/OWLFBRuleReasoner> ] ; 39 ja:baseModel :graph ; 40 . 41 42 What I have found is that if data is entered into the default graph in the "Data" dataset without the unionDefaultGraph option, this "Reasoner" dataset (above) will find the information and perform inferences over it. However, if the data is instead entered into two named graphs, with the unionDefaultGraph:true option selected, the "Reasoner" dataset is unable to find the information in "Data". Additionally, the "Reasoner" dataset has no access to read or write to the "Data" dataset, which is why I set up a separate end-point to be able to manipulate the data in "Data". The goal of this experiment is to be able to run different Owl ontologies over the same entity data, so ideally there would be a way to create a unionized graph from two named graphs in "Data" and query time, and then run the inference engine over this graph. So my questions are, 1) Is there a way to create a unionized graph at query time? If yes, is there a way to run an inference engine over this query-time-created unionized graph? 2) If the above is not an option, is there a way have an inference engine run over the unionized default graph from a set of named graphs? If you have any questions or need more information please feel free to reach out to me at any time. Thank you for your help, Evan Woodward
