Re: Reading triples, getting quads / reading quads, getting triples

[Andy Seaborne <an...@apache.org>]

On 23/12/12 02:04, Al Baker wrote:
> Definitely not QT3 and TQ3 - should do 1 or 2 and make them symmetrical.  I
> like QT1 and TQ1, with perhaps an optional parameter somewhere that can
> specify the named graph for quads.
>
> The default graph approach also aligns with other assumptions in Jena that
> don't force you into naming graphs but rather assume the default graph.
>
> Al

Implemented:
  QT1
  TQ1 with a warning (once per parse run) that NG quads are being ignored.

The other forms are all doable with the right implementation of 
StreamRDF, the new parser output interface.

	Andy

>
> On Sat, Dec 22, 2012 at 2:40 PM, Andy Seaborne <
> andy.seaborne@epimorphics.com> wrote:
>
>> (quads means a dataset).
>>
>> There is a debate in RDF-WG about what happens when a client wants triples
>> and the source is quads (a dataset) and the other way round - the client
>> wants quads, but gets triples.  This is is most pronounced in JSON-LD,
>> while formally is dataset syntax, has no graph equivalent, so it is likely
>> that graphs will be published for JSON using a dataset format.
>>
>> So, if the app reads into dataset ... but the target is a triples format
>> should RIOT:
>>
>> QT1 - read into default graph
>> QT2 - create a graph with the name of the target are put the triples there
>> QT3 - error (= provide machinery for the app to choose but have no default)
>>
>> If the app reads into a model ... and the target is quads:
>>
>> TQ1 - read just the default graph of the dataset (the asserted triples, in
>> some people's view)
>> TQ2 - project the quads into the output graph (union of all named graphs
>> and default graph).
>> TQ3 - error
>>
>> These all seem to make some sense at some times, and there are possibly
>> other designs.  I'm currently leaning toward QT1 (read into dft graph) and
>> TQ1 (read only the dft graph).
>>
>>          Andy
>>
>