xkos-best-practice.md

XKOS Best Practice

Introduction

This document describes some best practices for representing statistical classifications as XKOS. Where appropriate, a SPARQL query is provided: for a conformant RDF dataset, the query associated to compulsory rules should return no results.

Classifications and classifications schemes

• All classification schemes MUST have a skos:notation property which value is the short name of the classification scheme with no language tag.

Associated query:

PREFIX skos:<http://www.w3.org/2004/02/skos/core#>

SELECT ?s {
  ?s rdf:type skos:ConceptScheme .
  MINUS {
    SELECT ?s {
      ?s rdf:type skos:ConceptScheme .
      ?s skos:notation ?code .
    }
  }
}

• All classification schemes MUST have a skos:prefLabel property which value is the complete name of the classification scheme in English, with a language tag set at '@en'. Names in other languages MAY be provided with the same property. All names MUST have a language tag.

Associated query:

PREFIX skos:<http://www.w3.org/2004/02/skos/core#>

SELECT ?s {
  ?s rdf:type skos:ConceptScheme .
  MINUS {
    SELECT ?s {
      ?s rdf:type skos:ConceptScheme .
      ?s skos:prefLabel ?label .
      FILTER (LANG(?label)="en")
    }
  }
}

• All classification schemes MAY have additional labels represented by values of the skos:altLabel property. The SKOS integrity rules MUST be applied. The XKOS specification gives rules regarding the representation of fixed-length labels.

• All classification schemes SHOULD have a dc:description property which value is the short descriptive text about the classification scheme in English, with a language tag set at '@en'. Description in other languages MAY be provided with the same property. All descriptive texts MUST have a language tag.

Associated query:

PREFIX skos:<http://www.w3.org/2004/02/skos/core#>
PREFIX dc:<http://purl.org/dc/elements/1.1/>

SELECT ?s {
  ?s rdf:type skos:ConceptScheme .
  MINUS {
    SELECT ?s {
      ?s rdf:type skos:ConceptScheme .
      ?s dc:description ?description .
      FILTER (LANG(?description)="en")
    }
  }
}

• All classification schemes SHOULD have a skos:scopeNote property which value is a resource of type xkos:ExplanatoryNote. The explanatory note MUST have a xkos:plainText property which value is a long descriptive text about the classification scheme in English, with a language tag set at '@en'. Long descriptives in other languages MAY be provided: for each language a dedicated xkos:ExplanatoryNote resource will be created, with a xkos:plainText string bearing the corresponding language tag.

Associated query:

TBD

• All classification schemes MUST have a dcterms:issued property which value is the publication date of the of the classification scheme with datatype xsd:date.

Associated query:

PREFIX skos:<http://www.w3.org/2004/02/skos/core#>
PREFIX dcterms:<http://purl.org/dc/terms/>

SELECT ?s {
  ?s rdf:type skos:ConceptScheme .
  MINUS {
    SELECT ?s {
      ?s rdf:type skos:ConceptScheme .
      ?s dcterms:issued ?issued . 
    }
  }
}

• All classification schemes SHOULD have a dcterms:modified property which value is the last modification date of the of the classification scheme with datatype xsd:date.

Associated query:

PREFIX skos:<http://www.w3.org/2004/02/skos/core#>
PREFIX dcterms:<http://purl.org/dc/terms/>

SELECT ?s {
  ?s rdf:type skos:ConceptScheme .
  MINUS {
    SELECT ?s {
      ?s rdf:type skos:ConceptScheme .
      ?s dcterms:modified ?modified . 
    }
  }
}