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Re: Three solution designs to the first three Graphs use cases

From: Andy Seaborne <andy.seaborne@epimorphics.com>
Date: Wed, 01 Feb 2012 13:58:04 +0000
Message-ID: <4F2944EC.4040101@epimorphics.com>
To: public-rdf-wg@w3.org


On 01/02/12 13:40, David Wood wrote:
>>>> >>>    <s>   <p>   {<a>   <b>   <c>   }
>>>> >>>
>>>> >>>  you mint an identifier (<g1>   ) then store these quads:
>>>> >>>
>>>> >>>    <s>   <p>   <g1>   DEFAULT
>>>> >>>    <a>   <b>   <c>   <g1>
>>> >>
>>> >>
>>> >>  For what it is worth, this is what Mulgara does.
>> >
>> >  David,
>> >
>> >  Does Mulgara claim to support graph literals?
> Mulgara supports what it calls named graphs.  In fact, you*can't*  query Mulgara (or its predecessors) without querying a particular graph.  Our original query language (TQL) forced you to name a graph; the SPARQL implementation defaults to the default graph as configured, I believe.  Each quad is indexed with its graph membership.
>
> There are some "special" graphs in Mulgara, especially the "system" graph that stores triples about all the graphs that the system holds.  They are exposed and queryable.
>
>> >
>> >  What does
>> >
>> >  SELECT ?o {<s>  <p>  ?o }
>> >
>> >  return?
> If you queried the system graph thusly you would get the list of graph URIs held by that Mulgara instance.

Query the configured default graph.

Does ?o return  {<a>   <b>   <c>   } or <g1> or something else?

(By the way - is the data syntax for graph literals understood by 
Mulgara documented anywhere?)

	Andy
Received on Wednesday, 1 February 2012 13:58:31 UTC

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