Little Problem with SparQL rules

[Agustin pretto]

Hi Guys How are you?? 

I have a little problem ( could be a syntax problem) when I try to execute a Query based in a SparQl rule...

More exactly, I defined my ontology like this:

Class:

• Point

DataTypeProperties: ( Domain -> Range)

• X ( Point -> Double)
• Y ( Point -> Double)
  

Object Properties: ( Domain -> Range)

• equalTo (Point -> Point)

ok... and says that I have 2 individuals ( P1 and P2) with same X and Y

if I try a query like below, to find which Points have same coordinates:

PREFIX : //load the prefix

SELECT ?p1 ?p2

WHERE{

   ?p1 a :Point.

   ?p2 a :Point.

   ?p1 :X ?x1.

   ?p2 :X ?x2.

   ?p1 :Y ?y1.

   ?p2 :Y ?y2.

   FILTER ( (?x1 = ?x2) && (?y1 = ?y2) && ( ?p1 != ?p2) )

}

it Works FINE!!! and lists P1 and P2.... But if I put the where statement in a rule to define the "equalTo" objectProperty like this:

 

@prefix rule: <tag:stardog:api:rule:> .

[] a rule:SPARQLRule ;

rule:content """

PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>

PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

PREFIX : //Ontology Prefix goes here

IF {

   ?p1 a :Point.

   ?p2 a :Point.

   ?p1 :X ?x1.

   ?p2 :X ?x2.

   ?p1 :Y ?y1.

   ?p2 :Y ?y2.

   FILTER ( (?x1 = ?x2) && (?y1 = ?y2) && ( ?p1 != ?p2) )

}

THEN 

{

  ?p1 :equalTo ?p2.

} """.

Now If I try the same query with the "equalTo" ObjectProperty should return the same result... 

PREFIX : //load the prefix

SELECT ?p1 ?p2

WHERE{

   ?p1 :equalTo ?p2.

}

but always retun 0 rows...

I don't understand what I'm doing wrong in this... or there's some limitations in stardog with the rule definitions? 

Thanks

Agustin

[Héctor Pérez-Urbina]

Hi,

I created a test case with your rule and a minimal set of data (a X x1, b X x1, a Y x2, b Y x2) and it is producing the expected results. Are you using the reasoning level SL? Are you storing the rule in a particular named graph?

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Best,
Héctor

[Agustin pretto]

Hi Héctor, how're you?

I'm using the SL reasoning Level for the query, but still have the same results ( TT___TT).
I Upload the Ontology and the rule that I defined... Can you take a look??

Notes:

this is the query that gives the correct results... (2 rows)

select *
where {

?p1 a :Point.
    ?p2 a :Point.
    ?p1 :X ?x1.

    ?p1 :Y ?y1.

    ?p2 :X ?x2.
    ?p2 :Y ?y2.
       

        FILTER ((?x1 = ?x2) && (?y1 = ?y2)&& (?p1 != ?p2)).
}


and this is the query that I try to do... ( shoul return the same results) ( 0 rows)


select *
where {

?p1 a :Point.
    ?p2 a :Point.

    ?p1 :equalTo ?p2.
}

Thanks

Agustin

[Héctor Pérez-Urbina]

Thanks for the files. It turned out your rule is not syntactically valid. Simply remove the '.' after '<http://www.semanticweb.org/pc/ontologies/PointOntology.owl#>'.

[Agustin pretto]

Great! It Works...

Now (again) I have some trouble in the rule definition... I need to add a filter with not exists statement, but it doesn't return anything.

The Exists its available to use in the rule definition?

Greeting

Agustin

[Mike Grove]

Stardog rules have the same expressivity as SWRL rules so you can only have BGPs or FILTER expressions in your rule body.

Cheers,

Mike

 

Greeting