[tracker/wip/jfelder/external-reference: 13/14] 90-tracker.ontology: Add support for ExternalReference

[Jean Felder <jfelder src gnome org>]

commit 1d54e890de9d8577ff0ae34e60867cc138a68e22
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Jul 15 11:43:10 2019 +0200

    90-tracker.ontology: Add support for ExternalReference
    
    tracker#ExternalReference allows to introduce references to
    identifiers provided by an online service.
    
    For example, one can map a nmm#MusicAlbum with its Release Group Id
    provided by MusicBrainz (https://musicbrainz.org/doc/Release_Group).

 src/ontologies/nepomuk/90-tracker.ontology | 31 ++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)
---
diff --git a/src/ontologies/nepomuk/90-tracker.ontology b/src/ontologies/nepomuk/90-tracker.ontology
index 78e0c30e5..7eaa7e09b 100644
--- a/src/ontologies/nepomuk/90-tracker.ontology
+++ b/src/ontologies/nepomuk/90-tracker.ontology
@@ -8,7 +8,7 @@
 @prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
 
 tracker: a tracker:Ontology ;
-       nao:lastModified "2018-09-30T13:00:00Z" .
+       nao:lastModified "2019-07-15T09:41:00Z" .
 
 tracker:isDefaultTag a rdf:Property ;
        rdfs:domain nao:Tag ;
@@ -59,4 +59,31 @@ fts: a tracker:Namespace ;
 tracker:extractor-data-source a nie:DataSource ;
        rdfs:label "Tracker extractor data source" .
 
-nao:predefined-tag-favorite a nao:Tag .
\ No newline at end of file
+nao:predefined-tag-favorite a nao:Tag .
+
+tracker:ExternalReference a rdfs:Class ;
+        rdfs:label "External reference" ;
+        rdfs:comment "External reference to online services" ;
+        rdfs:subClassOf nie:InformationElement .
+
+tracker:referenceIdentifier a rdf:Property ;
+        rdfs:label "Identifier" ;
+        rdfs:comment "Identifier of the external reference" ;
+        nrl:maxCardinality 1 ;
+        rdfs:subPropertyOf nie:identifier ;
+        rdfs:domain tracker:ExternalReference ;
+        rdfs:range xsd:string .
+
+tracker:referenceSource a rdf:Property ;
+        rdfs:label "Source" ;
+        rdfs:comment "Source of the external reference (eg. 'Musicbrainz')" ;
+        nrl:maxCardinality 1 ;
+        rdfs:subPropertyOf nie:identifier ;
+        rdfs:domain tracker:ExternalReference ;
+        rdfs:range rdfs:Resource .
+
+tracker:hasExternalReference a rdf:Property ;
+        rdfs:label "External reference link" ;
+        rdfs:comment "Links the information element with the external reference" ;
+        rdfs:domain nie:InformationElement ;
+        rdfs:range tracker:ExternalReference .