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Specifying RDF Datasets

From: Ron Alford <ronwalf@umd.edu>
Date: Wed, 27 Jul 2005 13:32:53 -0400
Message-ID: <42E7C545.8080503@umd.edu>
To: undisclosed-recipients:;
There seems to be a discrepency between specifying RDF Datasets in the
query and in the protocol.

Quoted from http://www.w3.org/2001/sw/DataAccess/rq23/#unnamedGraph :
If a query provides more than one FROM clause, providing more than IRI
to indicate the default graph, then the default graph is based on the
RDF merge of the graphs obtained from representations of the resources
identified by the given IRIs.

Then from http://www.w3.org/2001/sw/DataAccess/proto-wd/ :
The RDF dataset is composed of one default or background RDF graph,
identified by one default-graph-uri type; and by zero or more named RDF
graphs, identified by zero or more named-graph-uri types. These
correspond to the FROM and FROM NAMED keywords in [SPARQL], respectively.

Also, from the wsdl snippets:
<xs:element minOccurs="0" maxOccurs="1" name="default-graph-uri"
type="xs:anyURI"></xs:element>


It appears you can specify multiple uris to be merged into the default
graph in the query, but can only specify one default graph uri in the
protocol parameters.


So some questions:

1) Should the protocol allow multiple default-graph-uri parameters?

2) Where, if anywhere, should the protocol document be referring to IRI
instead of URI?

3) (Mostly disjoint from the above) Would it be appropriate for an
implementation to provide a default dataset for clients to query (this
would answer "(can there be zero datasets?)")?


Thanks,
-Ron


Received on Wednesday, 27 July 2005 17:33:13 GMT

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