I have an RDF file where the resources are identified with nodeID's instead of URIs. I have imported them into Ontotext graphdb, and would like to generate URIs based on the nodeID (which I preserved during import). For example, I am trying to map this triple
_:C00456 rdf:type skos:Concept
to this:
<https://example.com/data/C00456> rdf:type skos:Concept
Unfortunately, if ?s is a BNODE, STR(?s) is an empty string in graphdb. xsd:string(?s), ditto. IRI(?s), you guessed it. Is there any function that will expose the form of the bnode as a string, so that I can build a URI from it? I went through the list of functions in the sparql 1.1 specification and could not see any.
PS It would have been nice if graphdb would just convert the nodeIDs to URIs during import (I specified a prefix for relative names), but it went by the book and turned them into bnodes. If I overlooked something, I'll be glad to be set right.
You can use the spif:buildString function to convert a BNode to String and then to IRI.
Here is a sample query:
PREFIX spif: <http://spinrdf.org/spif#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
CONSTRUCT {?sIRI ?p ?o} WHERE {
?s ?p ?o .
FILTER (isBlank(?s))
BIND (IRI(spif:buildString("http://my/namespace/{?1}", ?s)) as ?sIRI)
} LIMIT 10
The function is documented here:
https://graphdb.ontotext.com/documentation/10.0/sparql-functions-reference.html?highlight=buildstring#sparql-spin-functions-and-magic-predicates
Related
I am querying an ontology on the Bioportal endpoint. The ontology (NIF) is stored as a graph, so I put it in the FROM clause as the endpoint instructed.
SELECT DISTINCT ?p
FROM <http://bioportal.bioontology.org/ontologies/NIF>
WHERE{
?p a rdf:Property
}
limit 100
However, as can be seen below, the results came back showing few properties related to NIF and others to a different ontology called SKOS (Simple Knowledge Organization System).
In the Bioportal documentation it is said it maps some properties to SKOS properties, so I thought maybe the results are fine.
However, I had to test if I am querying the correct graph. So I used the below code to count the number of nodes since I know the NIF has around 3.6 million triples!
SELECT (count (*) as ?nodes)
FROM <http://bioportal.bioontology.org/ontologies/NIF>
WHERE{
?s ?p ?o
}
This resulted in 7984 nodes with and without the FROM clause! So I guessed I should be using the "count" incorrectly!
So I wonder how I should make sure that I am just querying the NIF ontology. Also, how to count its nodes?
Thanks :)
Try using SERVICE keyword.
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT (count (*) as ?nodes)
WHERE
{
SERVICE <http://bioportal.bioontology.org/ontologies/NIF>
{
?s ?p ?o
}
}
If this fails, possibly the service you are connecting is not correct or up.
Try below example which connects to DBpedia:
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT (count (*) as ?nodes)
WHERE
{
SERVICE <http://DBpedia.org/sparql>
{
?s ?p ?o
}
}
By the way I can;t access URL http://bioportal.bioontology.org/ontologies/NIF. Seems to be unavailable or down.
How can i query a remote endpoint (like endpoints of DBPedia or Wikidata) and insert resulting triples in a local graph? So far, i know that there are commands like INSERT, ADD, COPY etc. which can be used for such tasks. What i don't understand is how to address a remote endpoint while updating my local graph. Could someone provide a minimum example or the main steps?
I'm using Apache Jena Fuseki v2 on Windows and this is my query so far:
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX wd: <http://www.wikidata.org/entity/>
INSERT
{ GRAPH <???> { ?s ?p ?o } } #don't know what to insert here for "GRAPH"
WHERE
{ GRAPH <???> #don't know what to insert here for "GRAPH" either
{ #a working example query for wikidata:
?s wdt:P31 wd:Q5. #humans
?s wdt:P54 wd:Q43310. #germans
?s wdt:P1344 wd:Q79859. #part of world cup 2014
?s ?p ?o.
}
}
My local endpoint i'm querying is http://localhost:3030/mylocaldb/update. I've read that /update is necessary to edit the database (i'm not sure if i understood that correctly though).
Is my approach correct so far? Or is more stuff like additional scripting outside SPARQL needed?
Taken from the SPARQL 1.1 Update W3C specs:
The syntax is
( WITH IRIref )?
INSERT QuadPattern
( USING ( NAMED )? IRIref )*
WHERE GroupGraphPattern
If the INSERT template specifies GRAPH blocks then these will be the graphs affected. Otherwise, the operation will be applied to the default graph, or, respectively, to the graph specified in the WITH clause, if one was specified. If no USING (NAMED) clause is present, then the pattern in the WHERE clause will be matched against the Graph Store, otherwise against the dataset specified by the USING (NAMED) clauses. The matches against the WHERE clause create bindings to be applied to the template for determining triples to be inserted (following the same rules as for DELETE/INSERT).
So this basically means, you can omit the GRAPH definition from the INSERT part if you want to store it in the default graph, otherwise it will be the graph in which you want to store the data.
Regarding the WHERE clause, usually you would have to use the SERVICE keyword here to apply federated querying on the Wikidata endpoint (https://query.wikidata.org/bigdata/namespace/wdq/sparql):
PREFIX wdt: <http://www.wikidata.org/prop/direct/>
PREFIX p: <http://www.wikidata.org/prop/>
PREFIX wd: <http://www.wikidata.org/entity/>
INSERT
{ ?s ?p ?o }
WHERE
{ SERVICE <https://query.wikidata.org/bigdata/namespace/wdq/sparql>
{ #a working example query for wikidata:
?s wdt:P31 wd:Q5. #humans
?s wdt:P54 wd:Q43310. #germans
?s wdt:P1344 wd:Q79859. #part of world cup 2014
?s ?p ?o.
}
}
I tested it with Apache Jena and it inserts 4462 triples into my local dataset.
Is there any graph that contains mappings between equivalent properties in DBPedia and Yago? My application requires to "merge" triples that express the same meaning in both datasets, but I couldn't find any.
The following query returns an empty result at the Yago endpoint and only very few entries at the DBPedia endpoint.
prefix owl: <http://www.w3.org/2002/07/owl#>
select ?s ?o
where {
?s owl:equivalentProperty ?o .
}
There are some tools that automatically generated mappings between classes and properties of DBpedia and Yago. You can download some of these files here:
Yago to DBpedia linking
Why does this SPARQL query return no data?
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>
PREFIX dbpedia: <http://dbpedia.org/resource/>
SELECT *
WHERE {
<http://dbpedia.org/resource/Louis,_Prince_of_Condé_(1530–1569)> dbpedia-owl:abstract ?abstract
}
LIMIT 1
If you look at the DBpedia page, it shows the person has an abstract. Is it to do with the brackets in the URL? If so, how can I get round this?
This URI does not lead to the same result as the DBpedia page - for what ever reason. You can see this with
PREFIX dbpedia-owl: <http://dbpedia.org/ontology/>
PREFIX dbpedia: <http://dbpedia.org/resource/>
SELECT *
WHERE {
<http://dbpedia.org/resource/Louis,_Prince_of_Condé_(1530–1569)> ?p ?o
}
LIMIT 100
But it has an owl:sameAs relation to
http://dbpedia.org/resource/Louis,_Prince_of_Cond%C3%A9_(1530%E2%80%931569)
That means if you use this URI in your query, it should work as expected. But you should indeed apply a FILTER on the language, e.g. 'en' for English abstracts.
As AKSW mentions, the resource actually doesn't have many properties, but is connected to the "canonical" version by an owl:sameAs link. You can keep using the IRI that you're using now, follow owl:sameAs in either direction to any of its equal resources (let's call them ?s), and then ask for the abstract of ?s. (And then it's not a bad idea to filter by language, if that's applicable.) You can do this with a query like this (note that the current DBpedia endpoint uses dbo:, now, not the older dbpedia-owl:):
select ?abstract where {
<http://dbpedia.org/resource/Louis,_Prince_of_Condé_(1530–1569)> (owl:sameAs|^owl:sameAs)* ?s .
?s dbo:abstract ?abstract .
filter langMatches(lang(?abstract),'en')
}
It does not have dbpedia-owl:abstract predicate. If you list its predicates you find the following properties:
http://www.w3.org/2002/07/owl#sameAs
http://xmlns.com/foaf/0.1/name
http://purl.org/dc/elements/1.1/description
http://dbpedia.org/ontology/alias
http://dbpedia.org/ontology/birthYear
http://dbpedia.org/ontology/deathYear
http://dbpedia.org/ontology/viafId
http://dbpedia.org/ontology/deathPlace
http://dbpedia.org/ontology/deathDate
http://dbpedia.org/ontology/birthPlace
http://dbpedia.org/ontology/birthDate
Hello everybody i'm using a SPARQL query to retrieve properties and values of a specified resource. For example if i ask for Barry White, i obtain: birth place, associatedBand, recordLabels and so on.
Instead for any instance such as "Hammerfall", i obtain only this results:
Query results
But i want properties and values as shown in this page: Correct results.
My query is:
PREFIX db: <http://dbpedia.org/resource/>
PREFIX prop: <http://dbpedia.org/property/>
PREFIX onto: <http://dbpedia.org/ontology/>
SELECT ?property ?value
WHERE { db:Hammerfall?property ?value }
Anyone can tell me how to access to the correct resource and obtain corrects properties and values in every case?
select ?p ?o { dbpedia:HammerFall ?p ?o }
SPARQL results
The particular prefix doesn't matter; I just used dbpedia: because it's predefined on the endpoint as http://dbpedia.org/resource/, just like your db:. The issue is that HammerFall has a majuscule F in the middle, but your query uses a miniscule f.
As an alternative, since the results for Hammerfall (with a miniscule f) do include
http://dbpedia.org/ontology/wikiPageRedirects http://dbpedia.org/resource/HammerFall
you could use a property path to follow any wikiPageRedirects paths:
select ?p ?v {
dbpedia:Hammerfall dbpedia-owl:wikiPageRedirects* ?hammerfall .
?hammerfall ?p ?v
}
SPARQL results
See Retrieving dbpedia-owl:type value of resource with dbpedia-owl:wikiPageRedirect value? for more about that approach.