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Re: practical problems with rdf:parseType="Collection" implementation

From: Graham Klyne <gk@ninebynine.org>
Date: Fri, 15 Aug 2003 15:16:38 +0100
Message-Id: <5.1.0.14.2.20030815150815.00b76558@127.0.0.1>
To: Steve Harris <S.W.Harris@ecs.soton.ac.uk>, www-rdf-interest@w3.org

At 09:32 14/08/03 +0100, Steve Harris wrote:

>On Tue, Aug 12, 2003 at 05:09:12 -0700, Garret Wilson wrote:
> > The design of rdf:List looks good in theory, but there are a few details
> > that make it a pain to implement---particularly, the way rdf#nil is used:
>
>Its also quite awkward to query for, eg. in RDQL. I guess we need some
>kind of idiom that means is a memeber of this list. Theres nothing that
>logically comes from the structure though, unlike with collections.

If you query raw RDF data using just RDQL or similar, I would have to agree.

FWIW, when I implemented some (in-memory) RDF-query software, I found it 
convenient to add special forms to query container- and list- 
membership.  Either of these could have been implemented using a 
combination of inference combined with simple data query.

With lists, these leaves the possibility that there may be a significant 
penalty for list membership queries based on (say) a relational database 
RDF store.  I suspect that this can be optimized in an implementation.

#g


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Graham Klyne          _________
GK@ninebynine.org  ___|_o_o_o_|_
                    \____________/
(nb Helva)       ~~~~~~~~~~~~~~~~~~   @Perivale, Grand Union Canal
Received on Friday, 15 August 2003 15:29:40 GMT

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