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RE: Query, rules and RDF datatyping

From: Seaborne, Andy <Andy_Seaborne@hplb.hpl.hp.com>
Date: Thu, 9 Oct 2003 13:31:18 +0100
Message-ID: <E864E95CB35C1C46B72FEA0626A2E808302503@0-mail-br1.hpl.hp.com>
To: "'Graham Klyne'" <gk@ninebynine.org>, "'Geoff Chappell'" <geoff@sover.net>, "'www-rdf-rules@w3.org'" <www-rdf-rules@w3.org>

Graham wrote:
> The other desideratum drives me is to separate the datatype-based
> inferences from the actual graph query, because I see them being
> implemented in very different ways.

The approach we have taken is to put inference in "inferencing models" and
issue the query over those models, not make inference part of query itself.
A rule that manifests a new property :totalCapacity from :seatedCapacity and
:standingCapacity.

Of course, queries are rules, in the theory sense, so this does amount to
having hierarchical models, with each asserting new statements and the top
interface retrungin variable bindings, not graphs.  Indeed, for Joseki, the
result of query is the matching subgraph, not the bindings directly so that
this composition can be continued.

Much of RDQL in Jena is about presentation - a syntax to exprss the query
that is familiar, and a way to return results (variable bindings) that is
familiar.  
Different query languages can make use of the same unerlying machinary,
including optimizations.  The path-like syntaxes would work over the same
core engine very well.

	Andy
Received on Thursday, 9 October 2003 08:33:38 UTC

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