Arhs Team created JENA-1496:
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Summary: Inference with SPARQL and GenericRuleReasoner gives
different results
Key: JENA-1496
URL: https://issues.apache.org/jira/browse/JENA-1496
Project: Apache Jena
Issue Type: Bug
Affects Versions: Jena 3.6.0
Reporter: Arhs Team
Attachments: DemoApplication.java
Hi,
we are trying to manually infer some properties based on the SKOS definition.
Some of our models are huge and cannot be handled by Jena.
We tried OWL reasoner (+micro, +mini) and binding the SKOS definition with
bindSchema, we also tried the GenericRuleReasoner with OWL reasoning
capabilities but nothing worked. Some inference never finished, was too slow or
the memory consumption was too big.
We are now trying to do a lightweight inference of some properties with SPARQL
queries or Rules defined in the GenericRuleReasoner (without OWL reasoning). In
the rules, we manually create the triples we need : a skos:narrower b -> b
skos:broader a, we don't define skos:narrower owl:subPropertyOf skos:broader
since we don't have reasoning capabilities enabled.
We tried a few things and we found some inconsistencies between how a model is
updated with SPARQL queries and the GenericRuleReasoner if the object is a
resource or a literal.
The attached DemoApplication.java gives the following result:
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==== Test adding reasoner inferred object literal - not added
Size model 1, print :
<http://url.com/one> <http://www.w3.org/2008/05/skos-xl#literalForm>
"http://url.com/two"; .
Size inf 2, print :
<http://url.com/one> <http://www.w3.org/2008/05/skos-xl#literalForm>
"http://url.com/two"; .
Add inf to model
Size new model 1, print :
<http://url.com/one> <http://www.w3.org/2008/05/skos-xl#literalForm>
"http://url.com/two"; .
Size deduction model : 1
==== Test adding reasoner inferred object resource - added
Size model 1, print :
<http://url.com/one> <http://www.w3.org/2008/05/skos-xl#literalForm>
<http://url.com/two> .
Size inf 2, print :
<http://url.com/two> a
<http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral> .
<http://url.com/one> <http://www.w3.org/2008/05/skos-xl#literalForm>
<http://url.com/two> .
Add inf to model
Size new model 2, print :
<http://url.com/one> <http://www.w3.org/2008/05/skos-xl#literalForm>
<http://url.com/two> .
<http://url.com/two> a
<http://www.w3.org/1999/02/22-rdf-syntax-ns#PlainLiteral> .
Size deduction model : 1
==== Test adding sparql inferred object literal - construct model empty
Size model 1
Size construct model 0
Add construct model to model
Size new model 1
==== Test adding sparql inferred object resource - added
Size model 1
Size construct model 1
Add construct model to model
Size new model 2
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When the object is a resource, a new triple is inferred, visible and can be
added to another model for both SPARQL update or GenericRuleReasoner.
When the object is a literal, the SPARQL construct query doesn't return
anything, the GenericRuleReasoner infers a triple but it is not visible when
printing the model and we cannot add the triple to another model. With the
generic rule reasoner, we can still see that there is a triple inferred in the
deduction model but we cannot do anything with it.
This is causing some troubles for us because we don't know how to handle that
kind of scenarios based on invalid initial query/rule.
Thank you.
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