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
