On Mon, Mar 2, 2009 at 3:24 AM, Markus Krötzsch <
mar...@semantic-mediawiki.org> wrote:
> On Montag, 2. März 2009, Sergey Chernyshev wrote:
> > I just upgraded TechPresentations.org to trunk SMW and have troubles
> using
> > imported vocabularies.
> >
> > Import page exists:
> > http://www.techpresentations.org/MediaWiki:Smw_import_foaf
> >
> > But [[imported from:foaf:homepage]] does not make any difference:
> > http://www.techpresentations.org/Property:Homepage
> >
> > I had to use [[has type::Type:URL]] to ensure type enforcement.
>
> There have indeed been some changes there somewhere around SMW 1.3/1.4. I
> assumed that this is a very rarely used feature, hence did not send any
> warnings. Effectively, there is currently no more datatype enforcement for
> imported properties and you always need to specify the property datatype
> explicitly.
OK, specifying a property datatype is OK and I can live with it although
having multiple properties inherit imported type is more elegant, I'd say.
This is the result of some internal clean up. We currently do not have an
> architecture that allows one datavalue to set further annotations (this is
> what needs to happen if imported-from statements shall lead to implicit
> has-
> type statements). I am unsure how to best achieve this in a clean way. The
> historic implementation was not clean, introducing various special cases
> during parsing.
This is quite bad - it means that there is no way to link to external
vocabulary except for having this mapping outside of the system.
As I said, I did not consider this as a used feature so far (simply because
> there are only few uses of the RDF export, which is the only thing that
> importing influences).
Too bad I didn't keep upgrading to notice it anytime sooner, but this is
crucial, I believe and just last Thursday I heard a person who considered
moving from SMW to Drupal just because their RDF export looked better (they
use Turtle by default).
I think we should not underestimate the support from classical Semantic Web
people who so far assume RDF export to be the only usable feature (not that
I agree with them ;)) and also want Sparql.
Cheers,
>
> Markus
>
I think RDF export is broken by itself - probably because of this very
problem - you can see xmlns:="" in the code on this page
http://www.techpresentations.org/Special:ExportRDF/Sergey_Chernyshev - it is
supposed to use FOAF for foaf:Person class and foaf:homepage as well as
foaf:blog and I see some broken RDF for them:
<swivt:Subject rdf:about="&wiki;Sergey_Chernyshev">
...
<rdf:type rdf:resource=""/>
< rdf:resource="http://www.sergeychernyshev.com/blog/"/>
< rdf:resource="http://www.sergeychernyshev.com/"/>
...
</swivt:Subject>
Seems like importing code is not completely removed - maybe it's easier to
fix it then completely remove? Where should I look?
Thank you,
Sergey
--
Sergey Chernyshev
http://www.sergeychernyshev.com/
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