[redland-dev] querying using bNodes (blank nodes)

Richard Newman r.newman at reading.ac.uk
Wed May 23 03:19:01 BST 2007


Chris,

   You cannot reuse blank node identifiers between two queries; if  
you want a persistent identifier that you can put into a query, *use  
a URI*, because that's what they are for.

   You can only reference blank nodes by description (at least in  
SPARQL). If "by description" is too slow, don't use bnodes.

   HTH,

-R

> So it seems that if I want to use SPARQL I can't split my query in  
> two - I would have to say
>
> 	WHERE { ?x1 rdfs:subClassOf [ rdf:type owl:Restriction ; .... ] }
>
> And avoid explicitly mentioning bnodes altogether. This isn't my  
> preferred way of doing things - there are too many combinations of  
> axioms and descriptions.


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