Re: RDF* implementations and PG/SA modes [was: Re: Apache Jena support for RDF*]

On Sun, Aug 9, 2020 at 6:45 PM Andy Seaborne <andy@apache.org> wrote:

>
>
> On 08/08/2020 14:49, thomas lörtsch wrote:
> >
>
> Credit to Stardog - they state clearly their coverage: subject position,
> not nesting, and they do support cascading deletion.
>

Indeed, both were deliberate design choices. Extending the support to cover
the object position and arbitrary nesting would be easy. We haven't done it
not because we saw any technical difficulties but because adding something
later is much easier (from the compatibility viewpoint) than taking it away.

The SA semantics is something we feel considerably less optimistic about.

Cheers,
Pavel


>
> AnzoGraph documentation suggests subject only ("Each edge can have up to
> 256 properties.")
>
> Most systems only show subject position examples (Jena included!)
>
> What we seem to have is two implementation approaches - systems
> annotating the triple, and systems with independent RDF* terms.
>
> (no judgement about which is best)
>
>       Andy
>
> >
> > Nobody seems to support mode switching. Stardog uses a modified RDF*
> syntax that unambiguously asserts the triple it annotates. >
> > Absolutely no guarantee that the list is correct, much less complete.
> > Additions and corrections obviously very welcome!
> >
> >
> > Thomas
> >
>
>