[tracker] Added nmm:albumArtist property

[Ivan Frade <ifrade src gnome org>]

commit 1aa5e976aedbb4f8f5ec7bbf4aa28e5a22291b58
Author: Ivan Frade <ivan frade nokia com>
Date:   Tue Oct 13 19:22:08 2009 +0300

    Added nmm:albumArtist property

 data/ontologies/38-nmm.ontology |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/data/ontologies/38-nmm.ontology b/data/ontologies/38-nmm.ontology
index 0d8634d..fec79fb 100644
--- a/data/ontologies/38-nmm.ontology
+++ b/data/ontologies/38-nmm.ontology
@@ -53,6 +53,15 @@ nmm:musicAlbum a rdf:Property ;
 	rdfs:domain nmm:MusicPiece ;
 	rdfs:range nmm:MusicAlbum .
 
+# Cardinality could be > 1 if we create one for album collectiosn
+nmm:albumArtist a rdf:Property ;
+	rdfs:label "artist" ;
+	rdfs:comment "main artists of the album" ;
+	nrl:maxCardinality 1 ;
+	rdfs:domain nmm:MusicAlbum ;
+	rdfs:range nmm:Artist .
+
+
 nmm:beatsPerMinute a rdf:Property ;
 	rdfs:label "Beats per minute" ;
 	rdfs:comment "beats per minute" ;