So, if I understand this correctly, if my data is:
<http://sample.com/p1> a :Person; name "Person A"; :nick "Buddy";
:status "Living" .
<http://sample.com/p2> a :Person; name "Person B"; :nick "Bro"; :status
"Living" .
<http://sample.com/p3> a :DeadPerson; name "Person C"; :nick "Butch";
:status "Dead" .
and I give the command:
construct {?s ?p ?o} where {?s ?p ?o minus {?s ?p
<http://xmlns.com/foaf/0.1/DeadPerson>}}"
then I should get the resultant graph:
<http://sample.com/p1> a :Person; name "Person A"; :nick "Buddy";
:status "Living" .
<http://sample.com/p2> a :Person; name "Person B"; :nick "Bro"; :status
"Living" .
Would this be correct? - Erich
On 12/11/13 4:25 AM, Andy Seaborne wrote:
On 11/12/13 02:56, Erich Bremer wrote:
In the following segment of code:
String queryString = "construct {?s a ?o} whereccc minus {?s a
<http://xmlns.com/foaf/0.1/Person>}}";
Query query = QueryFactory.create(queryString);
QueryExecution qe = QueryExecutionFactory.create(query,m);
Model whoa = qe.execConstruct();
Rather than remove just the pattern {?s a
<http://xmlns.com/foaf/0.1/Person>}, it removes all types as if the
MINUS pattern was {?s a ?p}
Sound like you want:
FILTER (?o != <http://xmlns.com/foaf/0.1/Person>)
which just excludes any (?s, ?o) row where ?o is foaf:Person.
MINUS will take the left-hand side "?s a ?o" and the right-hand side
{ ?s a foaf:Person}, and remove all rows from the LHS that match
(=join) with the RHS.
So it removes all rows involving ?s where there is a match for
{?s a <http://xmlns.com/foaf/0.1/Person>}
See also
FILTER NOT EXISTS {?s a <http://xmlns.com/foaf/0.1/Person>}
which applies a test to ?s for every row to see if can be matched.
In both MINUS and FILTER NOT EXISTS, ?o is not playing a part - it's
not mentioned in the negation side and, in this case, MINUS and FILTER
NOT EXISTS have the same outcome.
Andy
- Erich
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