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.
Anatoly
On ב', 2013-06-10 at 16:40 -0700, Ivan Frade wrote:
> Hi Anatoly,
>
>
>
> On Mon, Jun 10, 2013 at 3:56 PM, אנטולי קרסנר <tomback...@gmail.com>
> wrote:
> Hello Tracker team,
>
> I'm writing software which needs to be able to do queries over
> the data
> it generates. It needs to be able to test all the RDF data
> entered to
> the database, including inferred data.
>
> Tracker is just as store and doesn't have any reasoner, but it is not
> completely stupid:
>
>
> For example, if class B is a subclass of A, then I need the
> query
> resolver to be able to detect that "subClassOf" is inverse of
> "superClassOf"
>
> It understands subclasses. In this case, for example, asking for
> instances of A return instances of A and B.
>
> and answer queries like "which subclasses does A have".
>
>
> Yes, that query is easy, the information is in the ontology but ONLY
> for direct subclasses, no transitivity.
>
>
> And also for transitive relations, if the relation is
> A->B->C->D, be
> able to detect that A->D.
>
>
> This is not done by Tracker. You need to manually write your queries
> to follow the hierarchy. Tracker doesn't add any transitivity, you
> need to query it explicitely.
>
>
>
> Can Tracker do this reasoning? I mean, does it just store data
> "as is"
> or it detects and understands inverse relations, transitive
> relations,
> object types implied by relatio domain/range, etc.?
>
>
> Tracker understands those relations and can solve direct queries, but
> doesn't add any magic to follow transitivity. In other words, the
> SparQL query need to mention explicitely each relation it follows (but
> not the classes).
>
>
> Example:
>
> class A with property aToB
>
> class B with property bToC
>
>
> you can do a query like:
>
> SELECT ?a ?c WHERE {
>
> ?a a A;
>
> aToB ?x;
>
> cToC ?c.
> }
>
>
>
> Note how the properties are mentioned, but the class of ?x or ?c is
> not relevant.
>
>
>
> If not, how can I do reasoning (necessary for user-defined
> queries)?
>
>
> Not sure why do you need the reasoner. What kind of queries do you
> want to solve? Our approach is to take the user parameters and
> translate it into a SparQl query. That query can be very complex but
> that is invisible to the user.
>
>
> For example, "Give me all possible details of a contact" is one
> "click" to the user, but internally is is complex query full of
> optionals... still is solved without a reasoner.
>
>
>
> Hope this has helped,
>
>
> Ivan
>
>
>
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