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Re: ISSUE-105: Graph vs. dataset syntaxes

From: Pierre-Antoine Champin <pierre-antoine.champin@liris.cnrs.fr>
Date: Wed, 19 Dec 2012 11:25:23 +0100
Message-ID: <CA+OuRR886trz8cgFHEQdh44s+r8=1i3CD+SuO+Q_mN6b8P4EgA@mail.gmail.com>
To: Ivan Herman <ivan@w3.org>
Cc: Sandro Hawke <sandro@w3.org>, Markus Lanthaler <markus.lanthaler@gmx.net>, "public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
On Thu, Dec 13, 2012 at 8:07 PM, Ivan Herman <ivan@w3.org> wrote:

>
> On Dec 13, 2012, at 12:28 , Sandro Hawke wrote:
>
> > On 12/13/2012 06:35 AM, Ivan Herman wrote:
> >> I find this a sensible compromise...
> >>
> >
> > Me too.   It seems to me basically what SPARQL does, and why it's called
> the "default graph".
> >
> >> For Trig/Turtle this may not be formally relevant because, afaik, Trig
> will have its own media type.
>

Well, I think it *does* have an impact, especially because Trig has its own
media type:
if you GET something from the web, expecting a single graph, and getting
some Trig (which you can tell immediately from the media-type),
then this gives you guidance on how to handle it.


>> But, for example, if an extension of RDFa is defined some day including
> facilities for graphs, this is probably an approach to follow.
> >>
> >
> > If we agree with this resolution of ISSUE-105, I might suggest this is
> new information and warrants briefly re-visiting this issue:
> > RESOLVED: In TriG, triples of the dataset's default graph MUST be
> surrounded by curly braces.
> >
> > http://www.w3.org/2011/rdf-wg/meeting/2012-10-17#resolution_2
> >
> > ... because with this approach it's much more natural to treat the
> name-graph pairs as an ignorable addition to turtle.
> >
>
> +1
>

I would tend to agree, but I think I remember someone (Steve?) arguing
against it as they would like their parser to know from the start if they
are dealing with a graph or a dataset, even in the absence of media-type...
Which sounds like a reasonable use-case...

  pa


> Ivan
>
> >      -- Sandro
> >
> >> Ivan
> >>
> >> On Dec 5, 2012, at 13:13 , Markus Lanthaler wrote:
> >>
> >>
> >>> While JSON-LD is a dataset syntax we expect that in most cases it will
> be
> >>> used to express simple graphs. This might become problematic if a
> consumer
> >>> is unable to process datasets -- even in the case where the dataset
> consists
> >>> of only the default graph. In JSON-LD we resolved this issue by
> specifying
> >>> that a consumer expecting a graph, MUST ignore everything but the
> default
> >>> graph.
> >>>
> >>> This allows publishers to expose their graphs in, e.g., both JSON-LD
> and
> >>> Turtle. Summarized, the behavior of a consumer would be as follows:
> >>>
> >>> Exposed  |  Expected  |  behavior
> >>> ---------+------------+-----------
> >>> Data set |  graph     |  use default graph as graph, ignore rest
> >>> Data set |  data set  |  exposed = expected
> >>> Graph    |  data set  |  use graph as default graph in dataset
> >>> Graph    |  graph     |  exposed = expected
> >>>
> >>>
> >>> This might have consequences on how data should be modeled (what
> should be
> >>> put in the default graph and what in a named graph) but that's beyond
> the
> >>> scope of a syntax.
> >>>
> >>> I would therefore like to propose to standardize this behavior for all
> RDF
> >>> data set syntaxes.
> >>>
> >>>
> >>> Regards,
> >>> Markus
> >>>
> >>>
> >>> --
> >>> Markus Lanthaler
> >>> @markuslanthaler
> >>>
> >>>
> >>>
> >>
> >> ----
> >> Ivan Herman, W3C Semantic Web Activity Lead
> >> Home:
> >> http://www.w3.org/People/Ivan/
> >>
> >> mobile: +31-641044153
> >> FOAF:
> >> http://www.ivan-herman.net/foaf.rdf
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >
>
>
> ----
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> FOAF: http://www.ivan-herman.net/foaf.rdf
>
>
>
>
>
>
Received on Wednesday, 19 December 2012 10:25:52 GMT

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