Retrieve country code from RDF source recieved via Sparql query - sparql

Question

I have the following query on this endpoint https://data.bnf.fr/sparql/ :
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdagroup2elements: <http://rdvocab.info/ElementsGr2/>
PREFIX bio: <http://vocab.org/bio/0.1/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT distinct ?name ?nationality
WHERE {
?oeuvre dcterms:creator ?author.
?author foaf:name ?name.
?author rdagroup2elements:countryAssociatedWithThePerson ?nationality.
}
ORDER BY DESC (?mort) LIMIT 100
Which returns a list of authors with a nationality field that is itself another RDF source :
So, for the first author Jean Martin, I get this link to another RDF source, in the case for the country France : http://id.loc.gov/vocabulary/countries/fr
How could I modify the query to receive the country code (or country name, if not possible) instead of this link, in this case FR (or France)?

Answer 1

An alternative to extracting the country code from the URI, using "the Linked Data way":
The default graph of the endpoint https://data.bnf.fr/sparql/ doesn’t provide any data about the entities under the namespace http://id.loc.gov/vocabulary/countries/, but it provides entities under the namespace http://data.bnf.fr/vocabulary/countrycodes/, which have an owl:sameAs link to them.
For example:
<http://data.bnf.fr/vocabulary/countrycodes/fr> <http://www.w3.org/2002/07/owl#sameAs> <http://id.loc.gov/vocabulary/countries/fr> .
And these http://data.bnf.fr/vocabulary/countrycodes/ entities refer to the country code with skos:notation, and to the country name with skos:prefLabel (language-tagged).
For these cases, getting the country code would be possible with this property path:
?author rdagroup2elements:countryAssociatedWithThePerson/^owl:sameAs/skos:notation ?countryCode .
Unfortunately, only some rdagroup2elements:countryAssociatedWithThePerson values are under the http://id.loc.gov/vocabulary/countries/ namespace, while other values are under the http://data.bnf.fr/vocabulary/countrycodes/ namespace directly.
To find both cases, you could use UNION:
{ ?author rdagroup2elements:countryAssociatedWithThePerson/^owl:sameAs/skos:notation ?countryCode . }
UNION
{ ?author rdagroup2elements:countryAssociatedWithThePerson/skos:notation ?countryCode . }
The full query:
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdagroup2elements: <http://rdvocab.info/ElementsGr2/>
PREFIX bio: <http://vocab.org/bio/0.1/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT DISTINCT ?name ?countryCode
WHERE {
?oeuvre dcterms:creator ?author.
?author foaf:name ?name.
{ ?author rdagroup2elements:countryAssociatedWithThePerson/^owl:sameAs/skos:notation ?countryCode . }
UNION
{ ?author rdagroup2elements:countryAssociatedWithThePerson/skos:notation ?countryCode . }
}
LIMIT 100
(In case you didn’t intend it: Your query treats different persons with the same name and country as one entry. To prevent this, you could output the person’s URI.)

Answer 2

You can use SPARQL replace function:
SELECT ... (REPLACE(STR(?nationality), "http://id.loc.gov/vocabulary/countries/", "") AS ?nationalityShort)
WHERE ...
to extract the code from the url.
But you can as well link to this resource and retrieve additional fields from it like sos:notation in your case:
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX rdagroup2elements: <http://rdvocab.info/ElementsGr2/>
PREFIX bio: <http://vocab.org/bio/0.1/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX foaf: <http://xmlns.com/foaf/0.1/>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT distinct ?name ?nationalityCode
WHERE {
?oeuvre dcterms:creator ?author.
?author foaf:name ?name.
?author rdagroup2elements:countryAssociatedWithThePerson ?nationality.
?nationality skos:notation ?nationalityCode
}
ORDER BY DESC (?mort) LIMIT 100