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Dear Karen,

Follow these steps:


1) Go to this website:

	http://demo.openlinksw.com/sparql


2) Enter this URL in the "Default Graph URI" field:

	http://bibframe.org/resources/Ahx1405278232/bibframe.rdf


3) Paste (your) query into the "Query Text" field:

	PREFIX bf:   <http://bibframe.org/vocab/>
	SELECT ?subject ?label
	WHERE {
		?subject bf:providerName ?bnode .
         	?bnode bf:label ?label .
	}


4) Select "Run Query"


I get the expected results, so your SPARQL query seems fine (I merely 
added a PREFIX declaration).  Is it possible this is a problem specific 
to Protege?

Cordially,
Kevin


On 07/14/2014 10:52 AM, Karen Coyle wrote:
> I'm hoping someone on this list has the quick answer that will end my
> frustration ;-).
>
> I loaded some BIBFRAME records into Protege (desktop, 5.0, because
> earlier versions have problems in the RDF->OWL transform). I have this
> data:
>
> _:genid4 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
> <http://bibframe.org/vocab/Provider> .
> _:genid5 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
> <http://bibframe.org/vocab/Organization> .
> _:genid5 <http://bibframe.org/vocab/label> "Morrow" .
> _:genid4 <http://bibframe.org/vocab/providerName> _:genid5 .
> <http://bibframe.org/resources/Ahx1405278232/566369instance27>
> <http://bibframe.org/vocab/publication> _:genid4
>
> [more readable version]
>
> :instance27 bf:publication _:genid4 .
> _:genid4 bf:providerName _:genid5 .
> _:genid5 bf:label "Morrow" .
>
> I want to create a SPARQL query that will select the labels for
> bf:providerName. I thought it would be:
>
> SELECT ?subject ?label
>      WHERE { ?subject bf:providerName ?bnode .
>          ?bnode bf:label ?label . }
>
> But it turns out that this doesn't work. As I understand it, it is
> because blank nodes are "unnamed" and therefore do not identify a
> particular entity, and cannot be used more than once in a query. See:
> [1][2]
>
> I've hit a dead-end, but surely there is a solution -- possibly right in
> front of me but I'm not seeing it.
>
> Thanks,
> kc
>
>
> [1]
> http://answers.semanticweb.com/questions/1673/skolem-syntax-for-blank-nodes-in-sparql
>
> [2]
> http://stackoverflow.com/questions/20629437/sparql-query-with-blank-node-can-be-complex
>
>