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SPARQL 1.1: project expressions and type errors

From: Arjohn Kampman <arjohn.kampman@aduna-software.com>
Date: Fri, 30 Oct 2009 15:16:39 +0100
Message-ID: <4AEAF547.6040606@aduna-software.com>
To: public-rdf-dawg-comments@w3.org
Dear WG,

I was wondering how a SPARQL query engine should handle project
expressions that apply an operator to an incompatible argument. For
example with the following query with ?p bound to a URI:

    select ?s, datatype(?p) as ?q
    where { ?s ?p ?o }

I can think of two ways to handle this:
1) Produce a solution with ?q unbound
2) Do not produce solutions for these cases

What would be the best way to handle this?

Regards,

-- 
Arjohn Kampman, Senior Software Engineer
Aduna - Semantic Power
www.aduna-software.com
Received on Friday, 30 October 2009 14:17:16 GMT

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