Re: Making querying of annotations optional

> On 9. Aug 2024, at 13:02, Andy Seaborne <andy@apache.org> wrote:
> 
> 
> 
> On 08/08/2024 17:02, Thomas Lörtsch wrote:
>> tl;dr
>> =====
>> Querying annotated triples seems to always require its own BGP expression, no matter if the triple so annotated exists in the graph or not. It seems like the annotation can never be just an option, added to a query for simple triples.
>> Asked concretely: is there a way to make the ?src information optional in the query using annotation syntax? E.g. something like
>>  SELECT ?x ?age ?src
>>  WHERE { ?x foaf:age ?age  OPTIONAL {| :src ?src |} . }
> 
> The WG has not made a decision on the direction for data yet.
> The design of any feature is going to be sensitive to that decision and that could throw any design work away.
> 
>> QUERYING IN RDF*
>> ================
> 
> This can be investigated by trying it in Blazegraph and any other system that claimed "PG mode" during the CG phase.
> 
>> QUERYING IN RDF-star
>> ====================
> 
> > E.g. something like
>>  SELECT ?x ?age ?src
>>  WHERE { ?x foaf:age ?age  OPTIONAL {| :src ?src |} . }
> 
> What would the expansion of short-cut syntax look like?
> What would the algebra look like?
> 
> What about multiple reifier/annotation syntax?
> 
> And Peter's question. [1]
> Or is this a change to BGP matching itself?

All these questions are answered in my original mail [0], in the lines immediatly preceding 

> > E.g. something like
>>  SELECT ?x ?age ?src
>>  WHERE { ?x foaf:age ?age  OPTIONAL {| :src ?src |} . }


>> Best,
>> Thomas
> 

[0] https://lists.w3.org/Archives/Public/public-rdf-star-wg/2024Aug/0040.html

> [1] https://lists.w3.org/Archives/Public/public-rdf-star-wg/2024Aug/0041.html
> 
>

Received on Friday, 9 August 2024 11:45:00 UTC