Re: [Tracker] Basic Reasoning

[אנטולי קרס נר <tombackton gmail com>]

Hi,

On ד', 2013-06-12 at 11:08 +0100, Martyn Russell wrote:
> On 11/06/13 06:58, אנטולי קרסנר wrote:
> > Thanks, now I understand it better.
> >
> > I'm not sure I need a reasoner, I just need to be able to do queries
> > which don't rely on explicit relations and properties.
> >
> > To be honest, I didn't read much about SPARQL so maybe it can do
> > everything I need without reasoning... I asked just to be sure I can
> > implement the user queries I need.
> >
> > I guess I'll see when I get there and start using actual queries.
>
> Ivan is right, you would need to perform more than one query here. For 
> example:
>
>    $ tracker-sparql -q "select ?s where { ?s rdfs:subClassOf nfo:Document }"
>
>    Results:
>      http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#TextDocument
>      http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#Presentation
>      http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#Spreadsheet
>      http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#MindMap
>      http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#Note
>      http://www.semanticdesktop.org/ontologies/2007/03/22/nfo#HelpDocument
>
> I believe you would have to do it again for nfo:TextDocument and so on 
> to find out the classes there.

No problems, I can automate these queries and make them appear as a
single query.

> Sadly, I don't think we have a way to find the parent for a class right 
> now, it's one directional at the moment.

Then I guess I'll have to use my own storage, at least for some of the
data, and do all the problematic queries using that storage. But for now
Tracker is enough, as long as queries are as simple as "give me all
objects with a given property" or "give me all objects with this
property set to this value".

We'll see very soon :)

Anatoly