BeCarefulWithUseOfInferencingInVocabularies < LinkedData

---+ Best Practice: Be careful with the use of inferencing in RDF Vocabularies

*State:* Draft

*Contact:* [[https://jazz.net/wiki/bin/view/Main/NickCrossley][Nick Crossley]]

---++ Scope

This Best Practice discusses inappropriate usage of inferencing properties such as =rdfs:domain= and =rdfs:range= in RDF vocabularies.

---++ Recommendation

RDFS contains terms such as =rdfs:domain= and =rdfs:range=, which go beyond mere vocabulary definition and enter into the world of ontologies. The primary difference between a vocabulary and an ontology is that an ontology includes inference rules which let you infer new information from given information - that is, add new triples to those stated, rather than constrain data to some schema.

For more information on this, read [[https://pdfs.semanticscholar.org/be86/69c329e0b518271c89698f842424501c0773.pdf][OSLC Resource Shape - A language for defining constraints on Linked Data]].

In the light of this knowledge, be careful with the use of inferencing terms in vocabularies - they often do not mean what you might have thought they meant. In particular, do not use =rdfs:domain= or =rdfs:range= with multiple values when defining a vocabulary term for a property, since that infers the target of that property is of all mentioned types, not any one of them.

---++ Examples

Here is an example snippet of an RDF vocabulary document:

<verbatim>
@prefix oslc:         <http://open-services.net/ns/core#> .
@prefix oslc_qm:      <http://open-services.net/ns/qm#> .
@prefix oslc_rm:      <http://open-services.net/ns/rm#> .
@prefix rdfs:         <http://www.w3.org/2000/01/rdf-schema#> .
@prefix rdf:          <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

oslc_qm:validatesRequirement
  a rdf:Property ;
  rdfs:isDefinedBy    oslc_qm: ;
  rdfs:label          "validatesRequirement" ;
  rdfs:comment        "Requirement that is validated by the Test Case." ;
  rdfs:range          oslc_rm:Requirement ;
  rdfs:domain         oslc_qm:TestScript, oslc_qm:TestCase ;
  oslc:inverseLabel   "Validated By" .
</verbatim>

This states that the target of an =oslc_qm:validatesRequirement= property is _both_ an =oslc_qm:TestScript= _and_ an =oslc_qm:TestCase= - which is not what the author intended. It also implies that any resource using this property may be inferred to be an OSLC requirement - which could prevent reuse of this property for requirements from non-OSLC providers.

In this case, the vocabulary term would be better defined without the use of =rdfs:range= and =rdfs:domain=.

The shape for resources using this property *should* consider use of the =oslc:range= property to suggest likely target types for the values of the property.
---++ See Also

   * [[http://www.w3.org/TR/rdf-schema/][RDF Schema]]
   * [[https://pdfs.semanticscholar.org/be86/69c329e0b518271c89698f842424501c0773.pdf][OSLC Resource Shape - A language for defining constraints on Linked Data]]

This topic: LinkedData > WebHome > BestPractices > BeCarefulWithUseOfInferencingInVocabularies

History: r2 - 2019-09-09 - 15:26:15 - Main.ndjc

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