What is the URI of the default graph or whatever graph contains inferences in OWLIM-Lite?

I am trying to write a SPARQL query restricted to a named graph. But I would also like access to the inferences derived from that named graph. Actually, accessing all inferences is not a problem. My understanding from other answers is that inferences are put into the default graph. And it seems that they might be accessible via "http://www.ontotext.com/implicit> { ?s ?p ?o }" in OWLIM-SE. (http://answers.ontotext.com/questions/1069/implicit-graph-and-sameas-optimization)

Here is my test query that fails in OWLIM-Lite:

PREFIX obo:<http://purl.org/obo/owl/obo#>
PREFIX up:<http://purl.uniprot.org/core/>
PREFIX taxon:<http://purl.uniprot.org/taxonomy/>
SELECT (count(*) as ?count)
FROM <http://purl.roundup.hms.harvard.edu/roundup-qfo_2013_04>
FROM <http://www.ontotext.com/implicit>
WHERE {
<http://purl.uniprot.org/uniprot/P38398> obo:orthologous_to ?o .
}

Note that this query works without the FROM clauses, but that is not my question. :-)

Best regards, Todd

asked 22 Jun '13, 11:35

ToddDeLuca's gravatar image

ToddDeLuca
1111
accept rate: 0%


Hi Todd, sorry for the long delay! The issue here is that Owlim Lite lacks the system graphs of Owlim SE. So onto:implicit here is interpreted as an ordinary graph and I don't expect that you have it in your data, that is why you don't get what you expect.

In order to select the implicit statements in Owlim Lite you should subtract statements in named graphs from all statements. This will work in case all your explicit statements are put in named graphs. The operation is not easy to combine with your query because it requires that no FROM and FROM NAMED clauses are used.

This query selects all the implicit statements:

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
SELECT * {
  { select ?s ?p ?o { ?s ?p ?o } }
  MINUS
  { select ?s ?p ?o { GRAPH ?g { ?s ?p ?o } } }
}

If you want to use it as a sub-select in your query you should remove the FROM/FROM NAMED clauses and to use GRAPH instead.

link

answered 17 Jul '13, 10:42

Ruslan's gravatar image

Ruslan ♦
3272
accept rate: 25%

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Asked: 22 Jun '13, 11:35

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Last updated: 17 Jul '13, 10:42

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