It is desirable for certain properties to keep their values unique across all resources, this can be expressed by defining the properties as being a nrl:InverseFunctionalProperty.
ex:geneticInformation a rdf:Property, nrl:InverseFunctionalProperty; rdfs:domain ex:Eukaryote; rdfs:range xsd:string;
With that in place, no two resources can have the same value on the property.
# First insertion, this will succeed INSERT DATA { <drosophila> a ex:Eukariote; ex:geneticInformation "AGCT" } # This will fail INSERT DATA { <melanogaster> a ex:Eukariote; ex:geneticInformation "AGCT" }