Retrieve country code from RDF source recieved via Sparql query

Question

I have the following query on this endpoint https://data.bnf.fr/sparql/ :

PREFIX rdfs: 
PREFIX rdagroup2elements: 
PREFIX bio: 
PREFIX dcterms: 
PREFIX foaf: 
PREFIX xsd: 
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)?

Stefan - brox IT-Solutions · Answer

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:

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: 
PREFIX owl: 
PREFIX rdfs: 
PREFIX rdagroup2elements: 
PREFIX bio: 
PREFIX dcterms: 
PREFIX foaf: 
PREFIX xsd: 
    
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.)

Krzysztof Majewski · Answer

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: 
PREFIX rdfs: 
PREFIX rdagroup2elements: 
PREFIX bio: 
PREFIX dcterms: 
PREFIX foaf: 
PREFIX xsd: 

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

Retrieve country code from RDF source recieved via Sparql query

2 Answers