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Shapes Constraint Language (SHACL)

Shapes Constraint Language (SHACL) is a standard for describing Resource Description Framework (RDF) graphs and validating them against a set of conditions, provided in the form of an RDF graph and referred to as shapes graphs. RDF graphs that are validated against a shapes graph are referred to as data graphs. SHACL uses SPARQL to validate data graphs against shapes graphs.

Examples​

  • Cagle (2016) “Meet SHACL, the Next OWL”: The following instance describes a User shape requiring two properties: the presence of a single foaf:name as a string and of at least one foaf:mbox that is a valid email address.

        SHACL "User" shape:
        ex:UserShape
              a sh:Shape ;
             sh:property [
                  sh:predicate foaf:name ;
                  sh:datatype xsd:string ;
                  sh:minCount 1 ;
                  sh:maxCount 1 ;
                  ] ;
              sh:property [
                  sh:predicate foaf:mbox ;
                  sh:nodeKind sh:IRI ;
                  sh:minCount 1 ;
                   ] .

  • Cagle (2016) “Meet SHACL, the Next OWL”: The following instance would satisfy the SHACL statement. It passes because it meets the conditions laid out by the shape: one (and only one) foaf:name that is a string, and at least one foaf:mbox that is a web resource.

        inst:User1
             a foaf:Person ;
             foaf:name "Jane Doe" ;
             foaf:mbox mailto:jd@example.org> ;
             foaf:mbox mailto:janedoe@gmail.com> .

  • Cagle (2016) “Meet SHACL, the Next OWL”: The following instance would fail to satisfy the SHACL statement. This instance fails because there are two entries for foaf:name instead of one, thus breaking the sh:maxCount 1 rule.

        inst:User2
             a foaf:Person ;
             foaf:name "Sarah Doe", "Sara Doe" ;
             foaf:mbox mailto:sd@example.org> ;
             foaf:mbox mailto:sarahdoe@gmail.com> .

Further Resources​