Re: TPF and DBMSes (was Re: Hydra and Shapes)

>> By definition, a “multiple statement triple pattern fragment” does not exist.
>> http://www.hydra-cg.com/spec/latest/triple-pattern-fragments/#definition
> Assuming that having looked up the URI above, what I read implies the following isn't possible:
> 
> ?s ?p ?o.
> ?o ?p1 ?o2 .

It is purposely not possible to ask such a question directly to a triple pattern fragments server.
It is possible to ask such a question to a triple pattern fragments client.

> then you *seem* to be claiming that a single sentence (a triple pattern) is all that can be thrown at this variant of RDF data source.

A triple pattern is not the only thing you can ask an HDT file.
I know it's possible to efficiently get graph pattern as well, for instance.
But I'm not an HDT expert; those people are: http://www.rdfhdt.org/team/

> Thus, what happens to situations where more than one sentence (be it comprised of constants or variables) is required for seeking information from these HDT encoded RDF data sources?

Regardless of what the data source is,
possible algorithms for executing SPARQL queries
over triple pattern fragments are described here:
- http://linkeddatafragments.org/publications/ldow2014.pdf (recursive algorithm)
- http://linkeddatafragments.org/publications/iswc2014.pdf (iterator-based algorithm)

For HDT-specific advice, I'd direct you to the people mentioned above.

Best,

Ruben

Received on Monday, 24 November 2014 18:32:39 UTC