W3C home > Mailing lists > Public > public-rdf-dawg-comments@w3.org > March 2005

Re: Turtle Tuples: Turtle-based query result format

From: Arjohn Kampman <arjohn.kampman@aduna.biz>
Date: Wed, 23 Mar 2005 17:37:42 +0100
Message-ID: <42419B56.1030800@aduna.biz>
To: Dave Beckett <dave.beckett@bristol.ac.uk>
Cc: Dan Connolly <connolly@w3.org>, public-rdf-dawg-comments@w3.org

Dave Beckett wrote:
[...]
>>>Easy to write - although this may be true for those familiar with
>>>N3/Turtle style languages, this is a query result format and that's
>>>either being written by query processors (so easy to write isn't
>>>critical) or by query engine developers and people working on the SPARQL
>>>language and tests - a small group!
>>
>>The point that was being made is that the format would be easier to
>>write by these query processors. An XML format requires one to specify
>>any namespace prefixes at the start of the document, which makes it
>>harder to write in a streaming fashion.
> 
> I don't understand that, your turtle tuples has @prefix before the
> result body declaring namespaces.  Same issue with streaming as the XML
> VBR.  Or I guess you could add them later but you didn't choose to show
> them in the example.

Yup, @prefix directives would be allowed half-way in the document, just
like Turtle allows you to do. This way, the query engine only has to
look one row ahead to check if there are any URIs with namespaces that
haven't been seen before.

>>I agree, but please 'fix' this XML format (I don't like the "variables
>>as tags" thing very much, as I pointed out in an earlier mail to this
>>list:-) ).
> 
> That's under discussion in the DAWG already, as we are considering
> motivations to switch to a form where variable names are attribute
> values/element content; and also possibly (allow) adding xsi:type.

Good to hear that. I'll keep an eye on the discussion.

--
Arjohn
Received on Wednesday, 23 March 2005 16:38:14 GMT

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