c# - Limit the SPARQL query result to First level in hierarchy -

i'm using c# execute query on n3 data files. how can limit result first level of children of node. example:

project       |       |__ main       |      |__m1       |      |__m2       |          |__ sub           |__a           |  |__a1           |  |__a2           |            |__b           |__c           |  |__c1           |             |__d 

an example query result level of nodes sub:

 select ?object {   :sub rdfs:superclassof* ?object  } 

the result be:

          |__a           |  |__a1           |  |__a2           |            |__b           |__c           |  |__c1           |             |__d 

but want limit result first level of children this:

          |__a           |__b           |__c           |__d 

selecting paths of length one

the property path using * finds paths of length zeor or greater. if want paths of length one, remove *:

 select ?object {     :sub rdfs:superclassof ?object  } 

i'd note though rdfs defines rdfs:subclassof, not rdfs:superclassof you've used in query. i'll assume it's typo in question, though. think actual query you'd want would be:

select ?subclass {    ?subclass rdfs:subclassof :sub } 

selecting arbitrary length paths

the solutions in section based on an answer question finding position of elements in rdf list. consider data:

@prefix : <urn:ex:> .  :a :p :b, :c . :b :p :d, :e . 

this query finds chains on p along lengths of chains:

prefix : <urn:ex:>  select ?sub ?sup (count(?mid)-1 ?distance) {    ?sub :p* ?mid .   ?mid :p* ?sup . } group ?sub ?sup order ?sub ?sup  $ arq --data data.n3 --query query.sparql ------------------------ | sub | sup | distance | ======================== | :a  | :a  | 0        | | :a  | :b  | 1        | | :a  | :c  | 1        | | :a  | :d  | 2        | | :a  | :e  | 2        | | :b  | :b  | 0        | | :b  | :d  | 1        | | :b  | :e  | 1        | | :c  | :c  | 0        | | :d  | :d  | 0        | | :e  | :e  | 0        | ------------------------ 

since can length of paths can filter on length , ones want. instance:

prefix : <urn:ex:>  select ?sub ?sup {    {      select ?sub ?sup (count(?mid)-1 ?distance) {        ?sub :p* ?mid .       ?mid :p* ?sup .     }     group ?sub ?sup     order ?sub ?sup   }   filter( ?distance = 2 )   # filter ( ?distance > 2 )   # alternative   # filter ( ?distance < 10 )  # alternative }  $ arq --data data.n3 --query query.sparql ------------- | sub | sup | ============= | :a  | :d  | | :a  | :e  | ------------- 

when want paths of small, specific length, can expand property path manually. e.g., paths of length two:

prefix : <urn:ex:>  select ?sub ?sup {   ?sub :p/:p ?sup . } 

for range of numbers, e.g., 1­–2, can use ? matches 0 or one:

prefix : <urn:ex:>  select ?sub ?sup {   ?sub :p/:p? ?sup . } 

for more property paths, sure take @ section 9 property paths in sparql 1.1 specification.