diff --git a/README.md b/README.md
index 67585370..55d72afa 100644
--- a/README.md
+++ b/README.md
@@ -13,8 +13,9 @@ A [demo](http://lms.demo.poupon.io) instance is available, with the following li
 - Audio transcode for maximum interoperability and low bandwith requirements
 - Persistent play queue across sessions
 - Subsonic API
-- Multi-value tags
-- Custom tag support (ex: "mood", "genre", "albummood", "albumgrouping", ...)
+- Album artist
+- Multi-value tags (artists, genres, ...)
+- Custom tags (ex: "mood", "genre", "albummood", "albumgrouping", ...)
 - MusicBrainzID support to handle duplicated artist and release names
 - Playlists (only using Subsonic API for now)
 
diff --git a/approot/artist.xml b/approot/artist.xml
index ef4d8032..63b88005 100644
--- a/approot/artist.xml
+++ b/approot/artist.xml
@@ -22,7 +22,7 @@
 					<h4 class="media-heading">
 						${name class="Lms-explore-releasename"}
 					</h4>
-					${<if-has-various-artists>}<h4><small><i>${tr:Lms.Explore.various-artists}</i></small></h4>${</if-has-various-artists>}
+					${<if-has-artist>}<h4><small>${artist class="Lms-explore-artistname"}</small></h4>${</if-has-artist>}
 					<h4><small>${<if-has-year>}${year}${</if-has-year>}${<if-has-orig-year>} (${orig-year})${</if-has-orig-year>}</small></h4>
 					${play-btn}${add-btn}
 				</div>
diff --git a/approot/release.xml b/approot/release.xml
index 5f66366e..9360d5c5 100644
--- a/approot/release.xml
+++ b/approot/release.xml
@@ -14,7 +14,7 @@
 	</div>
 	<div class="page-header">
 		<h3>${name}</h3>
-		${<if-has-artist>}<h4><i>${artist-name class="Lms-explore-artistname"}</i></h4>${</if-has-artist>}
+		${<if-has-artist>}<h4>${artist class="Lms-explore-artistname"}</h4>${</if-has-artist>}
 		<h4><small>${<if-has-year>}${year}${</if-has-year>}${<if-has-orig-year>} (${orig-year})${</if-has-orig-year>}</small></h4>
 		${clusters}
 		${play-btn}${add-btn}
diff --git a/src/Makefile.am b/src/Makefile.am
index f7c70bd8..105296dd 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,6 +21,8 @@ lms_SOURCES = \
 	$(srcdir)/database/Cluster.hpp				\
 	$(srcdir)/database/DatabaseHandler.cpp			\
 	$(srcdir)/database/DatabaseHandler.hpp			\
+	$(srcdir)/database/TrackArtistLink.cpp			\
+	$(srcdir)/database/TrackArtistLink.hpp			\
 	$(srcdir)/database/TrackFeatures.cpp			\
 	$(srcdir)/database/TrackFeatures.hpp			\
 	$(srcdir)/database/TrackList.cpp			\
diff --git a/src/database/Artist.cpp b/src/database/Artist.cpp
index 13b2fe04..c4a9d861 100644
--- a/src/database/Artist.cpp
+++ b/src/database/Artist.cpp
@@ -77,7 +77,7 @@ Artist::getAll(Wt::Dbo::Session& session, boost::optional<std::size_t> offset, b
 std::vector<Artist::pointer>
 Artist::getAllOrphans(Wt::Dbo::Session& session)
 {
-	Wt::Dbo::collection<Artist::pointer> res = session.query< Wt::Dbo::ptr<Artist> >("SELECT DISTINCT a FROM artist a WHERE NOT EXISTS(SELECT 1 FROM track t INNER JOIN track_artist t_a ON t_a.artist_id = a.id WHERE t.id = t_a.track_id)");
+	Wt::Dbo::collection<Wt::Dbo::ptr<Artist>> res {session.query<Wt::Dbo::ptr<Artist>>("SELECT DISTINCT a FROM artist a WHERE NOT EXISTS(SELECT 1 FROM track t INNER JOIN track_artist_link t_a_l ON t_a_l.artist_id = a.id WHERE t.id = t_a_l.track_id)")};
 
 	return std::vector<pointer>(res.begin(), res.end());
 }
@@ -98,7 +98,7 @@ getQuery(Wt::Dbo::Session& session,
 
 	if (!clusterIds.empty())
 	{
-		oss << " INNER JOIN track t ON t_a.track_id = t.id INNER JOIN track_artist t_a ON t_a.artist_id = a.id INNER JOIN cluster c ON c.id = t_c.cluster_id INNER JOIN track_cluster t_c ON t_c.track_id = t.id";
+		oss << " INNER JOIN track t ON t.id = t_a_l.track_id INNER JOIN track_artist_link t_a_l ON t_a_l.artist_id = a.id INNER JOIN cluster c ON c.id = t_c.cluster_id INNER JOIN track_cluster t_c ON t_c.track_id = t.id";
 
 		WhereClause clusterClause;
 
@@ -110,7 +110,7 @@ getQuery(Wt::Dbo::Session& session,
 	oss << " " << where.get();
 
 	if (!clusterIds.empty())
-		oss << " GROUP BY t.id HAVING COUNT(*) = " << clusterIds.size();
+		oss << " GROUP BY t.id HAVING COUNT(DISTINCT c.id) = " << clusterIds.size();
 
 	oss << " ORDER BY a.sort_name COLLATE NOCASE";
 
@@ -124,6 +124,13 @@ getQuery(Wt::Dbo::Session& session,
 	return query;
 }
 
+std::vector<Artist::pointer>
+Artist::getByFilter(Wt::Dbo::Session& session, const std::set<IdType>& clusters)
+{
+	bool more;
+	return getByFilter(session, clusters, {}, {}, {}, more);
+}
+
 std::vector<Artist::pointer>
 Artist::getByFilter(Wt::Dbo::Session& session,
 		const std::set<IdType>& clusters,
@@ -152,7 +159,7 @@ Artist::getByFilter(Wt::Dbo::Session& session,
 std::vector<Artist::pointer>
 Artist::getLastAdded(Wt::Dbo::Session& session, Wt::WDateTime after, boost::optional<std::size_t> limit)
 {
-	Wt::Dbo::collection<Artist::pointer> res = session.query<Artist::pointer>("SELECT a from artist a INNER JOIN track_artist t_a ON t_a.artist_id = a.id INNER JOIN track t ON t.id = t_a.track_id")
+	Wt::Dbo::collection<Artist::pointer> res = session.query<Artist::pointer>("SELECT a from artist a INNER JOIN track_artist_link t_a_l ON t_a_l.artist_id = a.id INNER JOIN track t ON t.id = t_a_l.track_id")
 		.where("t.file_added > ?").bind(after)
 		.groupBy("a.id")
 		.orderBy("t.file_added DESC")
@@ -171,7 +178,8 @@ Artist::getReleases(const std::set<IdType>& clusterIds) const
 	WhereClause where;
 
 	std::ostringstream oss;
-	oss << "SELECT DISTINCT r FROM release r INNER JOIN artist a ON t_a.artist_id = a.id INNER JOIN track_artist t_a ON t_a.track_id = t.id INNER JOIN track t ON t.release_id = r.id";
+
+	oss << "SELECT DISTINCT r FROM release r INNER JOIN artist a ON a.id = t_a_l.artist_id INNER JOIN track_artist_link t_a_l ON t_a_l.track_id = t.id INNER JOIN track t ON t.release_id = r.id";
 
 	if (!clusterIds.empty())
 	{
@@ -190,32 +198,54 @@ Artist::getReleases(const std::set<IdType>& clusterIds) const
 	oss << " " << where.get();
 
 	if (!clusterIds.empty())
-		oss << " GROUP BY t.id HAVING COUNT(*) = " << clusterIds.size();
+		oss << " GROUP BY t.id HAVING COUNT(DISTINCT c.id) = " << clusterIds.size();
 
 	oss << " ORDER BY t.year,r.name";
 
 	Wt::Dbo::Query<Release::pointer> query = session()->query<Release::pointer>( oss.str() );
 
 	for (const std::string& bindArg : where.getBindArgs())
-	{
 		query.bind(bindArg);
-	}
 
-	Wt::Dbo::collection< Wt::Dbo::ptr<Release> > res = query;
+	Wt::Dbo::collection<Wt::Dbo::ptr<Release>> res = query;
 
-	return std::vector< Wt::Dbo::ptr<Release> > (res.begin(), res.end());
+	return std::vector<Wt::Dbo::ptr<Release>>(res.begin(), res.end());
 }
 
 std::vector<Wt::Dbo::ptr<Track>>
-Artist::getTracks() const
+Artist::getTracks(boost::optional<TrackArtistLink::Type> linkType) const
 {
-	Wt::Dbo::collection<Wt::Dbo::ptr<Track>> tracks {session()->query<Wt::Dbo::ptr<Track>>("SELECT t from Track t INNER JOIN artist a ON t_a.artist_id = a.id INNER JOIN track_artist t_a ON t_a.track_id = t.id INNER JOIN release r ON r.id = t.release_id")
+	assert(self());
+	assert(IdIsValid(self()->id()));
+	assert(session());
+
+	auto query {session()->query<Wt::Dbo::ptr<Track>>("SELECT DISTINCT t FROM track t INNER JOIN artist a ON a.id = t_a_l.artist_id INNER JOIN track_artist_link t_a_l ON t_a_l.track_id = t.id")
+		.where("a.id = ?").bind(self()->id())
+		.orderBy("t.year,t.release_id,t.disc_number,t.track_number")};
+
+	if (linkType)
+		query.where("t_a_l.type = ?").bind(*linkType);
+
+	Wt::Dbo::collection<Wt::Dbo::ptr<Track>> tracks {query.resultList()};
+
+	return std::vector<Wt::Dbo::ptr<Track>>(tracks.begin(), tracks.end());
+}
+
+std::vector<Wt::Dbo::ptr<Track>>
+Artist::getTracksWithRelease(boost::optional<TrackArtistLink::Type> linkType) const
+{
+	assert(self());
+	assert(IdIsValid(self()->id()));
+	assert(session());
+
+	Wt::Dbo::collection<Wt::Dbo::ptr<Track>> tracks {session()->query<Wt::Dbo::ptr<Track>>("SELECT t FROM track t INNER JOIN artist a ON a.id = t_a_l.artist_id INNER JOIN track_artist_link t_a_l ON t_a_l.track_id = t.id INNER JOIN release r ON r.id = t.release_id")
 		.where("a.id = ?").bind(self()->id())
 		.orderBy("t.year,r.name,t.disc_number,t.track_number")};
 
 	return std::vector<Wt::Dbo::ptr<Track>>(tracks.begin(), tracks.end());
 }
 
+
 std::vector<Wt::Dbo::ptr<Track>>
 Artist::getRandomTracks(boost::optional<std::size_t> count) const
 {
@@ -223,7 +253,7 @@ Artist::getRandomTracks(boost::optional<std::size_t> count) const
 	assert(IdIsValid(self()->id()));
 	assert(session());
 
-	Wt::Dbo::collection<Wt::Dbo::ptr<Track>> tracks {session()->query<Wt::Dbo::ptr<Track>>("SELECT t from Track t INNER JOIN artist a ON t_a.artist_id = a.id INNER JOIN track_artist t_a ON t_a.track_id = t.id")
+	Wt::Dbo::collection<Wt::Dbo::ptr<Track>> tracks {session()->query<Wt::Dbo::ptr<Track>>("SELECT t from track t INNER JOIN artist a ON a.id = t_a_l.artist_id INNER JOIN track_artist_link t_a_l ON t_a_l.track_id = t.id")
 		.where("a.id = ?").bind(self()->id())
 		.orderBy("RANDOM()")
 		.limit(count ? static_cast<int>(*count) : -1)};
@@ -241,7 +271,7 @@ Artist::getClusterGroups(std::vector<ClusterType::pointer> clusterTypes, std::si
 	WhereClause where;
 
 	std::ostringstream oss;
-	oss << "SELECT  c from cluster c INNER JOIN track t ON c.id = t_c.cluster_id INNER JOIN track_cluster t_c ON t_c.track_id = t.id INNER JOIN cluster_type c_type ON c.cluster_type_id = c_type.id INNER JOIN artist a ON t_a.artist_id = a.id INNER JOIN track_artist t_a ON t_a.track_id = t.id";
+	oss << "SELECT c FROM cluster c INNER JOIN track t ON c.id = t_c.cluster_id INNER JOIN track_cluster t_c ON t_c.track_id = t.id INNER JOIN cluster_type c_type ON c.cluster_type_id = c_type.id INNER JOIN artist a ON t_a_l.artist_id = a.id INNER JOIN track_artist_link t_a_l ON t_a_l.track_id = t.id";
 
 	where.And(WhereClause("a.id = ?")).bind(std::to_string(self()->id()));
 	{
@@ -252,7 +282,7 @@ Artist::getClusterGroups(std::vector<ClusterType::pointer> clusterTypes, std::si
 		where.And(clusterClause);
 	}
 	oss << " " << where.get();
-	oss << "GROUP BY c.id ORDER BY COUNT(c.id) DESC";
+	oss << "GROUP BY c.id ORDER BY COUNT(DISTINCT c.id) DESC";
 
 	Wt::Dbo::Query<Cluster::pointer> query = session()->query<Cluster::pointer>( oss.str() );
 
diff --git a/src/database/Artist.hpp b/src/database/Artist.hpp
index 0b27f280..529728d3 100644
--- a/src/database/Artist.hpp
+++ b/src/database/Artist.hpp
@@ -27,15 +27,16 @@
 #include <Wt/WDateTime.h>
 #include <Wt/Dbo/Dbo.h>
 
+#include "TrackArtistLink.hpp"
 #include "Types.hpp"
 
 namespace Database
 {
 
-class Track;
 class Cluster;
 class ClusterType;
 class Release;
+class Track;
 
 class Artist : public Wt::Dbo::Dbo<Artist>
 {
@@ -50,6 +51,8 @@ class Artist : public Wt::Dbo::Dbo<Artist>
 		static pointer			getByMBID(Wt::Dbo::Session& session, const std::string& MBID);
 		static pointer			getById(Wt::Dbo::Session& session, IdType id);
 		static std::vector<pointer>	getByName(Wt::Dbo::Session& session, const std::string& name);
+		static std::vector<pointer> 	getByFilter(Wt::Dbo::Session& session,
+								const std::set<IdType>& clusters);		// at least one track that belongs to  these clusters
 		static std::vector<pointer> 	getByFilter(Wt::Dbo::Session& session,
 								const std::set<IdType>& clusters,		// at least one track that belongs to  these clusters
 								const std::vector<std::string>& keywords,	// name must match all of these keywords
@@ -65,9 +68,9 @@ class Artist : public Wt::Dbo::Dbo<Artist>
 		const std::string& getName(void) const { return _name; }
 		const std::string& getMBID(void) const { return _MBID; }
 
-		// Get the releases that have at least one track for this artist that belongs to optional cluster filters
 		std::vector<Wt::Dbo::ptr<Release>>	getReleases(const std::set<IdType>& clusterIds = std::set<IdType>()) const;
-		std::vector<Wt::Dbo::ptr<Track>>	getTracks() const;
+		std::vector<Wt::Dbo::ptr<Track>>	getTracks(boost::optional<TrackArtistLink::Type> linkType = {}) const;
+		std::vector<Wt::Dbo::ptr<Track>>	getTracksWithRelease(boost::optional<TrackArtistLink::Type> linkType = {}) const;
 		std::vector<Wt::Dbo::ptr<Track>>	getRandomTracks(boost::optional<std::size_t> count) const;
 
 		// Get the cluster of the tracks made by this artist
@@ -89,7 +92,7 @@ class Artist : public Wt::Dbo::Dbo<Artist>
 				Wt::Dbo::field(a, _name, "sort_name");
 				Wt::Dbo::field(a, _MBID, "mbid");
 
-				Wt::Dbo::hasMany(a, _tracks, Wt::Dbo::ManyToMany, "track_artist", "", Wt::Dbo::OnDeleteCascade);
+				Wt::Dbo::hasMany(a, _trackArtistLinks, Wt::Dbo::ManyToOne, "artist");
 			}
 
 	private:
@@ -100,7 +103,7 @@ class Artist : public Wt::Dbo::Dbo<Artist>
 		std::string _sortName;
 		std::string _MBID;	// Musicbrainz Identifier
 
-		Wt::Dbo::collection<Wt::Dbo::ptr<Track>> _tracks; // Tracks of this artist
+		Wt::Dbo::collection<Wt::Dbo::ptr<TrackArtistLink>> _trackArtistLinks; // Tracks involving this artist
 };
 
 } // namespace Database
diff --git a/src/database/Cluster.cpp b/src/database/Cluster.cpp
index 102e6f5e..014fec9a 100644
--- a/src/database/Cluster.cpp
+++ b/src/database/Cluster.cpp
@@ -108,6 +108,12 @@ ClusterType::getByName(Wt::Dbo::Session& session, std::string name)
 	return session.find<ClusterType>().where("name = ?").bind(name);
 }
 
+ClusterType::pointer
+ClusterType::getById(Wt::Dbo::Session& session, IdType id)
+{
+	return session.find<ClusterType>().where("id= ?").bind(id);
+}
+
 std::vector<ClusterType::pointer>
 ClusterType::getAll(Wt::Dbo::Session& session)
 {
diff --git a/src/database/Cluster.hpp b/src/database/Cluster.hpp
index 104d6d24..82f6b122 100644
--- a/src/database/Cluster.hpp
+++ b/src/database/Cluster.hpp
@@ -89,6 +89,7 @@ class ClusterType : public Wt::Dbo::Dbo<ClusterType>
 
 		static std::vector<pointer> getAllOrphans(Wt::Dbo::Session& session);
 		static pointer getByName(Wt::Dbo::Session& session, std::string name);
+		static pointer getById(Wt::Dbo::Session& session, IdType id);
 		static std::vector<pointer> getAll(Wt::Dbo::Session& session);
 
 		static pointer create(Wt::Dbo::Session& session, std::string name);
diff --git a/src/database/DatabaseHandler.cpp b/src/database/DatabaseHandler.cpp
index e4166263..41675d33 100644
--- a/src/database/DatabaseHandler.cpp
+++ b/src/database/DatabaseHandler.cpp
@@ -39,6 +39,7 @@
 #include "ScanSettings.hpp"
 #include "SimilaritySettings.hpp"
 #include "Track.hpp"
+#include "TrackArtistLink.hpp"
 #include "TrackList.hpp"
 #include "TrackFeatures.hpp"
 
@@ -106,6 +107,7 @@ Handler::Handler(Wt::Dbo::SqlConnectionPool& connectionPool)
 	_session.mapClass<TrackListEntry>("tracklist_entry");
 	_session.mapClass<Release>("release");
 	_session.mapClass<Track>("track");
+	_session.mapClass<TrackArtistLink>("track_artist_link");
 	_session.mapClass<TrackFeatures>("track_features");
 
 	_session.mapClass<ScanSettings>("scan_settings");
diff --git a/src/database/Release.cpp b/src/database/Release.cpp
index 34d315a5..bec8aa1d 100644
--- a/src/database/Release.cpp
+++ b/src/database/Release.cpp
@@ -73,7 +73,7 @@ Release::getAll(Wt::Dbo::Session& session, boost::optional<std::size_t> offset,
 {
 	Wt::Dbo::collection<pointer> res = session.find<Release>()
 		.offset(offset ? static_cast<int>(*offset) : -1)
-		.limit(size ? static_cast<int>(*size) : - 1)
+		.limit(size ? static_cast<int>(*size) : -1)
 		.orderBy("name COLLATE NOCASE");
 
 	return std::vector<pointer>(res.begin(), res.end());
@@ -83,7 +83,7 @@ std::vector<Release::pointer>
 Release::getAllRandom(Wt::Dbo::Session& session, boost::optional<std::size_t> size)
 {
 	Wt::Dbo::collection<pointer> res = session.find<Release>()
-		.limit(size ? static_cast<int>(*size) : - 1)
+		.limit(size ? static_cast<int>(*size) : -1)
 		.orderBy("RANDOM()");
 
 	return std::vector<pointer>(res.begin(), res.end());
@@ -183,6 +183,18 @@ Release::getByFilter(Wt::Dbo::Session& session,
 	return res;
 }
 
+boost::optional<std::size_t>
+Release::getTotalTrackNumber(void) const
+{
+	return (_totalTrackNumber > 0) ? boost::make_optional<std::size_t>(_totalTrackNumber) : boost::none;
+}
+
+boost::optional<std::size_t>
+Release::getTotalDiscNumber(void) const
+{
+	return (_totalDiscNumber > 0) ? boost::make_optional<std::size_t>(_totalDiscNumber) : boost::none;
+}
+
 boost::optional<int>
 Release::getReleaseYear(bool original) const
 {
@@ -249,16 +261,16 @@ Release::getCopyrightURL() const
 }
 
 std::vector<Wt::Dbo::ptr<Artist>>
-Release::getArtists() const
+Release::getArtists(TrackArtistLink::Type linkType) const
 {
 	assert(self());
 	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	Wt::Dbo::collection<Wt::Dbo::ptr<Artist>> res = session()->query<Wt::Dbo::ptr<Artist>>(
-			"SELECT DISTINCT a FROM artist a INNER JOIN release r ON t.id = t_a.track_id INNER JOIN track_artist t_a ON t_a.artist_id = a.id INNER JOIN track t ON t.release_id = r.id")
-		.where("r.id = ?")
-		.bind(id());
+			"SELECT DISTINCT a FROM artist a INNER JOIN track_artist_link t_a_l ON t_a_l.artist_id = a.id INNER JOIN track t ON t.id = t_a_l.track_id INNER JOIN release r ON r.id = t.release_id")
+		.where("r.id = ?").bind(self()->id())
+		.where("t_a_l.type = ?").bind(linkType);
 
 	return std::vector<Wt::Dbo::ptr<Artist>>(res.begin(), res.end());
 }
diff --git a/src/database/Release.hpp b/src/database/Release.hpp
index fc8def76..ae9d86c3 100644
--- a/src/database/Release.hpp
+++ b/src/database/Release.hpp
@@ -23,6 +23,7 @@
 
 #include <Wt/Dbo/WtSqlTraits.h>
 
+#include "TrackArtistLink.hpp"
 #include "Types.hpp"
 
 namespace Database
@@ -76,13 +77,20 @@ class Release : public Wt::Dbo::Dbo<Release>
 		boost::optional<std::string> getCopyright() const;
 		boost::optional<std::string> getCopyrightURL() const;
 
+		// Modifiers
+		void setTotalDiscNumber(std::size_t num)	{ _totalDiscNumber = static_cast<int>(num); }
+		void setTotalTrackNumber(std::size_t num)	{ _totalTrackNumber = static_cast<int>(num); }
+
 		// Accessors
-		std::string	getName() const		{ return _name; }
-		std::string	getMBID() const		{ return _MBID; }
+		std::string			getName() const		{ return _name; }
+		std::string			getMBID() const		{ return _MBID; }
+		boost::optional<std::size_t>	getTotalTrackNumber() const;
+		boost::optional<std::size_t>	getTotalDiscNumber() const;
 		std::chrono::milliseconds	getDuration() const;
 
 		// Get the artists of this release
-		std::vector<Wt::Dbo::ptr<Artist> > getArtists() const;
+		std::vector<Wt::Dbo::ptr<Artist> > getArtists(TrackArtistLink::Type type = TrackArtistLink::Type::Artist) const;
+		std::vector<Wt::Dbo::ptr<Artist> > getReleaseArtists() const { return getArtists(TrackArtistLink::Type::ReleaseArtist); }
 		bool hasVariousArtists() const;
 
 		void setMBID(std::string mbid) { _MBID = mbid; }
@@ -92,17 +100,21 @@ class Release : public Wt::Dbo::Dbo<Release>
 			{
 				Wt::Dbo::field(a, _name, "name");
 				Wt::Dbo::field(a, _MBID, "mbid");
+				Wt::Dbo::field(a, _totalDiscNumber,	"total_disc_number");
+				Wt::Dbo::field(a, _totalTrackNumber,	"total_track_number");
 
 				Wt::Dbo::hasMany(a, _tracks, Wt::Dbo::ManyToOne, "release");
 			}
 
 	private:
-		static const std::size_t _maxNameLength = 128;
+		static const std::size_t _maxNameLength {128};
 
-		std::string _name;
-		std::string _MBID;
+		std::string	_name;
+		std::string	_MBID;
+		int		_totalDiscNumber {};
+		int		_totalTrackNumber {};
 
-		Wt::Dbo::collection< Wt::Dbo::ptr<Track> > _tracks; // Tracks in the release
+		Wt::Dbo::collection<Wt::Dbo::ptr<Track>>	_tracks; // Tracks in the release
 };
 
 } // namespace Database
diff --git a/src/database/Track.cpp b/src/database/Track.cpp
index 738fc71f..4e1102b3 100644
--- a/src/database/Track.cpp
+++ b/src/database/Track.cpp
@@ -37,12 +37,13 @@ _filePath( p.string() )
 {
 }
 
-Wt::Dbo::collection< Track::pointer >
+std::vector<Track::pointer>
 Track::getAll(Wt::Dbo::Session& session, boost::optional<std::size_t> limit)
 {
-	int size {limit ? static_cast<int>(*limit) : -1};
+	Wt::Dbo::collection<Track::pointer> res {session.find<Track>()
+		.limit(limit ? static_cast<int>(*limit) : -1)};
 
-	return session.find<Track>().limit(size);
+	return std::vector<Track::pointer>(std::cbegin(res), std::cend(res));
 }
 
 std::vector<Track::pointer>
@@ -229,15 +230,24 @@ Track::getByFilter(Wt::Dbo::Session& session,
 {
 	bool moreResults;
 
-	return getByFilter(session, clusters, std::vector<std::string>{}, -1, -1, moreResults);
+	return getByFilter(session,
+			clusters,
+			std::vector<std::string> {},
+			boost::optional<std::size_t> {},
+			boost::optional<std::size_t> {},
+			moreResults);
 }
 
 void
-Track::setArtists(const std::vector<Wt::Dbo::ptr<Artist>>& artists)
+Track::clearArtistLinks()
 {
-	_artists.clear();
-	for (const Wt::Dbo::ptr<Artist>& artist : artists)
-		_artists.insert(artist);
+	_trackArtistLinks.clear();
+}
+
+void
+Track::addArtistLink(const Wt::Dbo::ptr<TrackArtistLink>& artistLink)
+{
+	_trackArtistLinks.insert(artistLink);
 }
 
 void
@@ -260,24 +270,12 @@ Track::getTrackNumber(void) const
 	return (_trackNumber > 0) ? boost::make_optional<std::size_t>(_trackNumber) : boost::none;
 }
 
-boost::optional<std::size_t>
-Track::getTotalTrackNumber(void) const
-{
-	return (_totalTrackNumber > 0) ? boost::make_optional<std::size_t>(_totalTrackNumber) : boost::none;
-}
-
 boost::optional<std::size_t>
 Track::getDiscNumber(void) const
 {
 	return (_discNumber > 0) ? boost::make_optional<std::size_t>(_discNumber) : boost::none;
 }
 
-boost::optional<std::size_t>
-Track::getTotalDiscNumber(void) const
-{
-	return (_totalDiscNumber > 0) ? boost::make_optional<std::size_t>(_totalDiscNumber) : boost::none;
-}
-
 boost::optional<int>
 Track::getYear() const
 {
@@ -303,9 +301,23 @@ Track::getCopyrightURL() const
 }
 
 std::vector<Wt::Dbo::ptr<Artist>>
-Track::getArtists() const
+Track::getArtists(TrackArtistLink::Type type) const
 {
-	return std::vector<Wt::Dbo::ptr<Artist>>(_artists.begin(), _artists.end());
+	assert(self());
+	assert(IdIsValid(self()->id()));
+	assert(session());
+
+	Wt::Dbo::collection<Wt::Dbo::ptr<Artist>> artists {session()->query<Artist::pointer>("SELECT a from artist a INNER JOIN track_artist_link t_a_l ON a.id = t_a_l.artist_id INNER JOIN track t ON t.id = t_a_l.track_id")
+		.where("t.id = ?").bind(self()->id())
+		.where("t_a_l.type = ?").bind(type)};
+
+	return std::vector<Wt::Dbo::ptr<Artist>>(artists.begin(), artists.end());
+}
+
+std::vector<Wt::Dbo::ptr<TrackArtistLink>>
+Track::getArtistLinks() const
+{
+	return std::vector<Wt::Dbo::ptr<TrackArtistLink>>(_trackArtistLinks.begin(), _trackArtistLinks.end());
 }
 
 Wt::Dbo::ptr<TrackFeatures>
diff --git a/src/database/Track.hpp b/src/database/Track.hpp
index e6026802..82686ecd 100644
--- a/src/database/Track.hpp
+++ b/src/database/Track.hpp
@@ -29,6 +29,7 @@
 #include <Wt/Dbo/Dbo.h>
 #include <Wt/WDateTime.h>
 
+#include "TrackArtistLink.hpp"
 #include "Types.hpp"
 
 namespace Database {
@@ -63,7 +64,7 @@ class Track : public Wt::Dbo::Dbo<Track>
 							boost::optional<std::size_t> size,
 							bool& moreExpected);
 
-		static Wt::Dbo::collection< pointer > getAll(Wt::Dbo::Session& session, boost::optional<std::size_t> limit = {});
+		static std::vector<pointer>	getAll(Wt::Dbo::Session& session, boost::optional<std::size_t> limit = {});
 		static std::vector<pointer>	getAllRandom(Wt::Dbo::Session& session, boost::optional<std::size_t> limit = {});
 		static std::vector<IdType>	getAllIds(Wt::Dbo::Session& session); // nested transaction
 		static std::vector<boost::filesystem::path> getAllPaths(Wt::Dbo::Session& session); // nested transaction
@@ -79,9 +80,7 @@ class Track : public Wt::Dbo::Dbo<Track>
 		// Accessors
 		void setScanVersion(std::size_t version)			{ _scanVersion = version; }
 		void setTrackNumber(int num)					{ _trackNumber = num; }
-		void setTotalTrackNumber(int num)				{ _totalTrackNumber = num; }
 		void setDiscNumber(int num)					{ _discNumber = num; }
-		void setTotalDiscNumber(int num)				{ _totalDiscNumber = num; }
 		void setName(const std::string& name)				{ _name = std::string(name, 0, _maxNameLength); }
 		void setDuration(std::chrono::milliseconds duration)		{ _duration = duration; }
 		void setLastWriteTime(Wt::WDateTime time)			{ _fileLastWrite = time; }
@@ -93,16 +92,15 @@ class Track : public Wt::Dbo::Dbo<Track>
 		void setMBID(const std::string& MBID)				{ _MBID = MBID; }
 		void setCopyright(const std::string& copyright)			{ _copyright = std::string(copyright, 0, _maxCopyrightLength); }
 		void setCopyrightURL(const std::string& copyrightURL)		{ _copyrightURL = std::string(copyrightURL, 0, _maxCopyrightURLLength); }
-		void setArtists(const std::vector<Wt::Dbo::ptr<Artist>>& artists);
+		void clearArtistLinks();
+		void addArtistLink(const Wt::Dbo::ptr<TrackArtistLink>& artistLink);
 		void setRelease(Wt::Dbo::ptr<Release> release)			{ _release = release; }
 		void setClusters(const std::vector<Wt::Dbo::ptr<Cluster>>& clusters );
 		void setFeatures(const Wt::Dbo::ptr<TrackFeatures>& features);
 
 		std::size_t 				getScanVersion() const		{ return _scanVersion; }
 		boost::optional<std::size_t>		getTrackNumber() const;
-		boost::optional<std::size_t>		getTotalTrackNumber() const;
 		boost::optional<std::size_t>		getDiscNumber() const;
-		boost::optional<std::size_t>		getTotalDiscNumber() const;
 		std::string 				getName() const			{ return _name; }
 		boost::filesystem::path			getPath() const			{ return _filePath; }
 		std::chrono::milliseconds		getDuration() const		{ return _duration; }
@@ -115,7 +113,8 @@ class Track : public Wt::Dbo::Dbo<Track>
 		const std::string&			getMBID() const			{ return _MBID; }
 		boost::optional<std::string>		getCopyright() const;
 		boost::optional<std::string>		getCopyrightURL() const;
-		std::vector<Wt::Dbo::ptr<Artist>>	getArtists() const;
+		std::vector<Wt::Dbo::ptr<Artist>>	getArtists(TrackArtistLink::Type type = {TrackArtistLink::Type::Artist}) const;
+		std::vector<Wt::Dbo::ptr<TrackArtistLink>>	getArtistLinks() const;
 		Wt::Dbo::ptr<Release>			getRelease() const		{ return _release; }
 		std::vector<Wt::Dbo::ptr<Cluster>>	getClusters() const;
 		bool					hasTrackFeatures() const;
@@ -128,9 +127,7 @@ class Track : public Wt::Dbo::Dbo<Track>
 			{
 				Wt::Dbo::field(a, _scanVersion,		"scan_version");
 				Wt::Dbo::field(a, _trackNumber,		"track_number");
-				Wt::Dbo::field(a, _totalTrackNumber,	"total_track_number");
 				Wt::Dbo::field(a, _discNumber,		"disc_number");
-				Wt::Dbo::field(a, _totalDiscNumber,	"total_disc_number");
 				Wt::Dbo::field(a, _name,		"name");
 				Wt::Dbo::field(a, _duration,		"duration");
 				Wt::Dbo::field(a, _year,		"year");
@@ -144,7 +141,7 @@ class Track : public Wt::Dbo::Dbo<Track>
 				Wt::Dbo::field(a, _copyright,		"copyright");
 				Wt::Dbo::field(a, _copyrightURL,	"copyright_url");
 				Wt::Dbo::belongsTo(a, _release, "release", Wt::Dbo::OnDeleteCascade);
-				Wt::Dbo::hasMany(a, _artists, Wt::Dbo::ManyToMany, "track_artist", "", Wt::Dbo::OnDeleteCascade);
+				Wt::Dbo::hasMany(a, _trackArtistLinks, Wt::Dbo::ManyToOne, "track");
 				Wt::Dbo::hasMany(a, _clusters, Wt::Dbo::ManyToMany, "track_cluster", "", Wt::Dbo::OnDeleteCascade);
 				Wt::Dbo::hasMany(a, _playlistEntries, Wt::Dbo::ManyToOne, "track");
 				Wt::Dbo::hasOne(a, _trackFeatures);
@@ -158,9 +155,7 @@ class Track : public Wt::Dbo::Dbo<Track>
 
 		int					_scanVersion = 0;
 		int					_trackNumber = 0;
-		int					_totalTrackNumber = 0;
 		int					_discNumber = 0;
-		int					_totalDiscNumber = 0;
 		std::string				_name;
 		std::string				_artistName;
 		std::string				_releaseName;
@@ -177,7 +172,7 @@ class Track : public Wt::Dbo::Dbo<Track>
 		std::string				_copyrightURL;
 
 		Wt::Dbo::ptr<Release>				_release;
-		Wt::Dbo::collection<Wt::Dbo::ptr<Artist>>	_artists;
+		Wt::Dbo::collection<Wt::Dbo::ptr<TrackArtistLink>> _trackArtistLinks;
 		Wt::Dbo::collection<Wt::Dbo::ptr<Cluster>> 	_clusters;
 		Wt::Dbo::collection<Wt::Dbo::ptr<TrackListEntry>> _playlistEntries;
 		Wt::Dbo::weak_ptr<TrackFeatures>		_trackFeatures;
diff --git a/src/database/TrackArtistLink.cpp b/src/database/TrackArtistLink.cpp
new file mode 100644
index 00000000..9ca3c26a
--- /dev/null
+++ b/src/database/TrackArtistLink.cpp
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2013-2016 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "TrackArtistLink.hpp"
+
+#include "Artist.hpp"
+#include "Track.hpp"
+
+namespace Database {
+
+TrackArtistLink::TrackArtistLink(Wt::Dbo::ptr<Track> track, Wt::Dbo::ptr<Artist> artist, Type type)
+: _type {type},
+_track {track},
+_artist {artist}
+{
+}
+
+TrackArtistLink::pointer
+TrackArtistLink::create(Wt::Dbo::Session& session, Wt::Dbo::ptr<Track> track, Wt::Dbo::ptr<Artist> artist,Type type)
+{
+	return session.add(std::make_unique<TrackArtistLink>(track, artist, type));
+}
+
+}
+
diff --git a/src/database/TrackArtistLink.hpp b/src/database/TrackArtistLink.hpp
new file mode 100644
index 00000000..65143f63
--- /dev/null
+++ b/src/database/TrackArtistLink.hpp
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2013-2016 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <Wt/Dbo/Dbo.h>
+
+#include "Types.hpp"
+
+namespace Database {
+
+class Artist;
+class Track;
+
+class TrackArtistLink
+{
+	public:
+		enum class Type
+		{
+			Artist,	// regular artist
+			Arranger,
+			Composer,
+			Conductor,
+			Lyricist,
+			Mixer,
+			Performer,
+			Producer,
+			ReleaseArtist,
+			Remixer,
+			Writer,
+		};
+
+		using pointer = Wt::Dbo::ptr<TrackArtistLink>;
+
+		TrackArtistLink() = default;
+		TrackArtistLink(Wt::Dbo::ptr<Track> track, Wt::Dbo::ptr<Artist> artist, Type type);
+
+		static pointer create(Wt::Dbo::Session& session, Wt::Dbo::ptr<Track> track, Wt::Dbo::ptr<Artist> artist,Type type);
+
+		Wt::Dbo::ptr<Track>	getTrack() const { return _track; }
+		Wt::Dbo::ptr<Artist>	getArtist() const { return _artist; }
+		Type			getType() const { return _type; }
+
+		template<class Action>
+		void persist(Action& a)
+		{
+			Wt::Dbo::field(a, _type, "type");
+			Wt::Dbo::field(a, _type, "name");
+
+			Wt::Dbo::belongsTo(a, _track, "track", Wt::Dbo::OnDeleteCascade);
+			Wt::Dbo::belongsTo(a, _artist, "artist", Wt::Dbo::OnDeleteCascade);
+		}
+
+	private:
+
+		Type		_type;
+		std::string	_name;
+
+		Wt::Dbo::ptr<Track> _track;
+		Wt::Dbo::ptr<Artist> _artist;
+};
+
+}
+
+
diff --git a/src/database/TrackList.cpp b/src/database/TrackList.cpp
index 8864bd8e..ca72b864 100644
--- a/src/database/TrackList.cpp
+++ b/src/database/TrackList.cpp
@@ -223,7 +223,7 @@ TrackList::getTopArtists(std::size_t limit) const
 	assert(session());
 	assert(IdIsValid(self()->id()));
 
-	Wt::Dbo::collection<Artist::pointer> res = session()->query<Artist::pointer>("SELECT a from artist a INNER JOIN track t ON t.id = t_a.track_id INNER JOIN track_artist t_a ON t_a.artist_id = a.id INNER JOIN tracklist_entry p_e ON p_e.track_id = t.id INNER JOIN tracklist p ON p.id = p_e.tracklist_id")
+	Wt::Dbo::collection<Artist::pointer> res = session()->query<Artist::pointer>("SELECT a from artist a INNER JOIN track t ON t.id = t_a_l.track_id INNER JOIN track_artist_link t_a_l ON t_a_l.artist_id = a.id INNER JOIN tracklist_entry p_e ON p_e.track_id = t.id INNER JOIN tracklist p ON p.id = p_e.tracklist_id")
 		.where("p.id = ?").bind(self()->id())
 		.groupBy("a.id")
 		.orderBy("COUNT(a.id) DESC")
diff --git a/src/main/main.cpp b/src/main/main.cpp
index 12883a10..89fb3be6 100644
--- a/src/main/main.cpp
+++ b/src/main/main.cpp
@@ -63,6 +63,8 @@ std::vector<std::string> generateWtConfig(std::string execPath)
 		args.push_back("--http-address=" + Config::instance().getString("listen-addr", "0.0.0.0"));
 	}
 
+	args.push_back("--gdb");
+
 	// Generate the wt_config.xml file
 	boost::property_tree::ptree pt;
 
diff --git a/src/scanner/MediaScanner.cpp b/src/scanner/MediaScanner.cpp
index 085885d5..bb9a0653 100644
--- a/src/scanner/MediaScanner.cpp
+++ b/src/scanner/MediaScanner.cpp
@@ -85,7 +85,7 @@ isPathInParentPath(const boost::filesystem::path& path, const boost::filesystem:
 }
 
 std::vector<Artist::pointer>
-getArtists(Wt::Dbo::Session& session, const std::vector<MetaData::Artist>& artistsInfo)
+getOrCreateArtists(Wt::Dbo::Session& session, const std::vector<MetaData::Artist>& artistsInfo)
 {
 	std::vector<Artist::pointer> artists;
 
@@ -129,7 +129,7 @@ getArtists(Wt::Dbo::Session& session, const std::vector<MetaData::Artist>& artis
 }
 
 Release::pointer
-getRelease(Wt::Dbo::Session& session, const MetaData::Album& album)
+getOrCreateRelease(Wt::Dbo::Session& session, const MetaData::Album& album)
 {
 	Release::pointer release;
 
@@ -166,7 +166,7 @@ getRelease(Wt::Dbo::Session& session, const MetaData::Album& album)
 }
 
 std::vector<Cluster::pointer>
-getClusters(Wt::Dbo::Session& session, const MetaData::Clusters& clustersNames)
+getOrCreateClusters(Wt::Dbo::Session& session, const MetaData::Clusters& clustersNames)
 {
 	std::vector< Cluster::pointer > clusters;
 
@@ -465,15 +465,18 @@ MediaScanner::scanAudioFile(const boost::filesystem::path& file, bool forceScan,
 	}
 
 	// ***** Clusters
-	std::vector<Cluster::pointer> clusters {getClusters(_db.getSession(), trackInfo->clusters)};
+	std::vector<Cluster::pointer> clusters {getOrCreateClusters(_db.getSession(), trackInfo->clusters)};
 
 	//  ***** Artists
-	std::vector<Artist::pointer> artists {getArtists(_db.getSession(), trackInfo->artists)};
+	std::vector<Artist::pointer> artists {getOrCreateArtists(_db.getSession(), trackInfo->artists)};
+
+	//  ***** Release artists
+	std::vector<Artist::pointer> releaseArtists {getOrCreateArtists(_db.getSession(), trackInfo->albumArtists)};
 
 	//  ***** Release
 	Release::pointer release;
 	if (trackInfo->album)
-		release = getRelease(_db.getSession(), *trackInfo->album);
+		release = getOrCreateRelease(_db.getSession(), *trackInfo->album);
 
 	// If file already exist, update data
 	// Otherwise, create it
@@ -493,11 +496,25 @@ MediaScanner::scanAudioFile(const boost::filesystem::path& file, bool forceScan,
 		stats.updates++;
 	}
 
+	// Release related data
+	if (release)
+	{
+		release.modify()->setTotalTrackNumber(trackInfo->totalTrack ? *trackInfo->totalTrack : 0);
+		release.modify()->setTotalDiscNumber(trackInfo->totalDisc ? *trackInfo->totalDisc : 0);
+	}
+
+	// Track related data
 	assert(track);
 
+	track.modify()->clearArtistLinks();
+	for (const auto& artist : artists)
+		track.modify()->addArtistLink(Database::TrackArtistLink::create(_db.getSession(), track, artist, Database::TrackArtistLink::Type::Artist));
+
+	for (const auto& releaseArtist : releaseArtists)
+		track.modify()->addArtistLink(Database::TrackArtistLink::create(_db.getSession(), track, releaseArtist, Database::TrackArtistLink::Type::ReleaseArtist));
+
 	track.modify()->setScanVersion(_scanVersion);
 	track.modify()->setChecksum(checksum);
-	track.modify()->setArtists(artists);
 	track.modify()->setRelease(release);
 	track.modify()->setClusters(clusters);
 	track.modify()->setLastWriteTime(lastWriteTime);
@@ -505,9 +522,7 @@ MediaScanner::scanAudioFile(const boost::filesystem::path& file, bool forceScan,
 	track.modify()->setDuration(trackInfo->duration);
 	track.modify()->setAddedTime(Wt::WLocalDateTime::currentServerDateTime().toUTC());
 	track.modify()->setTrackNumber(trackInfo->trackNumber ? *trackInfo->trackNumber : 0);
-	track.modify()->setTotalTrackNumber(trackInfo->totalTrack ? *trackInfo->totalTrack : 0);
 	track.modify()->setDiscNumber(trackInfo->discNumber ? *trackInfo->discNumber : 0);
-	track.modify()->setTotalDiscNumber(trackInfo->totalDisc ? *trackInfo->totalDisc : 0);
 	track.modify()->setYear(trackInfo->year ? *trackInfo->year : 0);
 	track.modify()->setOriginalYear(trackInfo->originalYear ? *trackInfo->originalYear : 0);
 
diff --git a/src/ui/explore/ArtistView.cpp b/src/ui/explore/ArtistView.cpp
index fdac71cf..5dc0a609 100644
--- a/src/ui/explore/ArtistView.cpp
+++ b/src/ui/explore/ArtistView.cpp
@@ -120,6 +120,7 @@ Artist::refresh()
 	Wt::WContainerWidget* releasesContainer = t->bindNew<Wt::WContainerWidget>("releases");
 
 	auto releases = artist->getReleases(_filters->getClusterIds());
+
 	for (auto release : releases)
 	{
 		auto releaseId = release.id();
@@ -139,8 +140,27 @@ Artist::refresh()
 
 		entry->bindWidget("name", LmsApplication::createReleaseAnchor(release));
 
-		if (release->hasVariousArtists())
-			entry->setCondition("if-has-various-artists", true);
+		auto artists {release->getReleaseArtists()};
+		LMS_LOG(UI, DEBUG) << "Found " << artists.size() << " release artists";
+
+		for (auto artist : artists)
+			LMS_LOG(UI, DEBUG) << "\tArtist = '" << artist->getName() << "'";
+
+		if (artists.empty())
+			artists = release->getArtists();
+
+		bool isSameArtist {(std::find(std::cbegin(artists), std::cend(artists), artist) != artists.end())};
+
+		if (artists.size() > 1)
+		{
+			entry->setCondition("if-has-artist", true);
+			entry->bindNew<Wt::WText>("artist", Wt::WString::tr("Lms.Explore.various-artists"));
+		}
+		else if (artists.size() == 1 && !isSameArtist)
+		{
+			entry->setCondition("if-has-artist", true);
+			entry->bindWidget("artist", LmsApplication::createArtistAnchor(artists.front()));
+		}
 
 		boost::optional<int> year = release->getReleaseYear();
 		if (year)
diff --git a/src/ui/explore/ReleaseLink.cpp b/src/ui/explore/ReleaseLink.cpp
index 16e44925..4930698b 100644
--- a/src/ui/explore/ReleaseLink.cpp
+++ b/src/ui/explore/ReleaseLink.cpp
@@ -44,7 +44,10 @@ ReleaseLink::ReleaseLink(Database::Release::pointer release)
 	cover->setWidth(48);
 	anchor->setImage(std::move(cover));
 
-	auto artists = release->getArtists();
+	auto artists = release->getReleaseArtists();
+	if (artists.empty())
+		artists = release->getArtists();
+
 	if (artists.size() > 1)
 	{
 		setCondition("if-has-artist", true);
diff --git a/src/ui/explore/ReleaseView.cpp b/src/ui/explore/ReleaseView.cpp
index 9fe68ce5..8de243ba 100644
--- a/src/ui/explore/ReleaseView.cpp
+++ b/src/ui/explore/ReleaseView.cpp
@@ -96,16 +96,21 @@ Release::refresh()
 	}
 
 	{
-		auto artists {release->getArtists()};
+		std::vector<Wt::Dbo::ptr<Database::Artist>> artists;
+
+		artists = release->getReleaseArtists();
+		if (artists.empty())
+			artists = release->getArtists();
+
 		if (artists.size() > 1)
 		{
 			t->setCondition("if-has-artist", true);
-			t->bindNew<Wt::WText>("artist-name", Wt::WString::tr("Lms.Explore.various-artists"));
+			t->bindNew<Wt::WText>("artist", Wt::WString::tr("Lms.Explore.various-artists"));
 		}
 		else if (artists.size() == 1)
 		{
 			t->setCondition("if-has-artist", true);
-			t->bindWidget("artist-name", LmsApplication::createArtistAnchor(artists.front()));
+			t->bindWidget("artist", LmsApplication::createArtistAnchor(artists.front()));
 		}
 	}
 
@@ -181,7 +186,7 @@ Release::refresh()
 		}
 
 		auto discNumber {track->getDiscNumber()};
-		auto totalDiscNumber {track->getTotalDiscNumber()};
+		auto totalDiscNumber {release->getTotalDiscNumber()};
 		if (discNumber && totalDiscNumber && *totalDiscNumber > 1)
 		{
 			entry->setCondition("if-has-disc-number", true);
diff --git a/src/ui/explore/ReleasesView.cpp b/src/ui/explore/ReleasesView.cpp
index e23eec66..205748f5 100644
--- a/src/ui/explore/ReleasesView.cpp
+++ b/src/ui/explore/ReleasesView.cpp
@@ -96,7 +96,10 @@ Releases::addSome()
 
 		entry->bindWidget("release-name", LmsApplication::createReleaseAnchor(release));
 
-		auto artists = release->getArtists();
+		auto artists = release->getReleaseArtists();
+		if (artists.empty())
+			artists = release->getArtists();
+
 		if (artists.size() > 1)
 		{
 			entry->setCondition("if-has-artist", true);
diff --git a/test/Makefile.am b/test/Makefile.am
index 06f44b52..ab7cd40b 100644
--- a/test/Makefile.am
+++ b/test/Makefile.am
@@ -1,14 +1,32 @@
 
-TESTS = som-test
+TESTS = som database
 
-check_PROGRAMS = som-test
+check_PROGRAMS = som database
 
-som_test_SOURCES = \
-	$(srcdir)/som-test/SomTest.cpp					\
+som_SOURCES = \
+	$(srcdir)/som/SomTest.cpp					\
 	$(top_srcdir)/src/similarity/features/som/DataNormalizer.cpp	\
 	$(top_srcdir)/src/similarity/features/som/Network.cpp
 
-som_test_CXXFLAGS=-std=c++14 -Wall -I${top_srcdir}/src/ -I${top_srcdir}/src/similarity/features/som/
+som_CXXFLAGS=-std=c++14 -Wall -I${top_srcdir}/src/ -I${top_srcdir}/src/similarity/features/som/
 
 
+database_SOURCES = \
+	$(srcdir)/database/DatabaseTest.cpp			\
+	$(top_srcdir)/src/database/Artist.cpp			\
+	$(top_srcdir)/src/database/Cluster.cpp			\
+	$(top_srcdir)/src/database/DatabaseHandler.cpp		\
+	$(top_srcdir)/src/database/TrackArtistLink.cpp		\
+	$(top_srcdir)/src/database/TrackFeatures.cpp		\
+	$(top_srcdir)/src/database/TrackList.cpp		\
+	$(top_srcdir)/src/database/Release.cpp			\
+	$(top_srcdir)/src/database/ScanSettings.cpp		\
+	$(top_srcdir)/src/database/SimilaritySettings.cpp	\
+	$(top_srcdir)/src/database/SqlQuery.cpp			\
+	$(top_srcdir)/src/database/Track.cpp			\
+	$(top_srcdir)/src/database/User.cpp			\
+	$(top_srcdir)/src/utils/Logger.cpp			\
+	$(top_srcdir)/src/utils/Utils.cpp
+
+database_CXXFLAGS=-std=c++14 -Wall -I${top_srcdir}/src/
 
diff --git a/test/database/DatabaseTest.cpp b/test/database/DatabaseTest.cpp
new file mode 100644
index 00000000..1d2ca1b9
--- /dev/null
+++ b/test/database/DatabaseTest.cpp
@@ -0,0 +1,948 @@
+/*
+ * Copyright (C) 2019 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <cstdlib>
+
+#include <boost/filesystem.hpp>
+
+#include "database/Artist.hpp"
+#include "database/Cluster.hpp"
+#include "database/DatabaseHandler.hpp"
+#include "database/TrackList.hpp"
+#include "database/Release.hpp"
+#include "database/Track.hpp"
+
+using namespace Database;
+
+class ScopedFileDeleter final
+{
+	public:
+		ScopedFileDeleter(const boost::filesystem::path& path) : _path {path} {}
+		~ScopedFileDeleter() { boost::filesystem::remove(_path); }
+	private:
+		boost::filesystem::path _path;
+};
+
+/*static void check(bool cond)
+{
+	if (!cond)
+}*/
+
+#define CHECK(PRED)  \
+{ \
+	if (!(PRED)) \
+	{ \
+		std::string msg {"Predicate '" + std::string {#PRED} + "' at " + __FUNCTION__ + "@l." + std::to_string(__LINE__)}; \
+		throw std::runtime_error(msg.c_str()); \
+	} \
+}
+
+static
+void
+testSingleTrack(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrackFile")};
+		CHECK(track);
+		session.flush();
+		trackId = track.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		CHECK(track);
+		CHECK(Track::getAll(session).size() == 1);
+
+		track.remove();
+	}
+}
+
+static
+void
+testSingleArtist(Wt::Dbo::Session& session)
+{
+	IdType artistId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::create(session, "MyArtist")};
+		CHECK(artist);
+		session.flush();
+		artistId = artist.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		CHECK(Artist::getAll(session).size() == 1);
+
+		auto artists {Artist::getAllOrphans(session)};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		CHECK(artist);
+		artist.remove();
+	}
+}
+
+static
+void
+testSingleRelease(Wt::Dbo::Session& session)
+{
+	IdType releaseId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto release {Release::create(session, "MyRelease")};
+		CHECK(release);
+		session.flush();
+		releaseId = release.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto releases {Release::getAllOrphans(session)};
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+
+		releases = Release::getAll(session);
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto release {Release::getById(session, releaseId)};
+		CHECK(release);
+		release.remove();
+	}
+}
+
+static
+void
+testSingleCluster(Wt::Dbo::Session& session)
+{
+	IdType clusterTypeId {};
+	IdType clusterId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto clusterType {ClusterType::create(session, "MyType")};
+		CHECK(clusterType);
+		auto cluster {Cluster::create(session, clusterType, "MyCluster")};
+		CHECK(cluster);
+		session.flush();
+		clusterTypeId = clusterType.id();
+		clusterId = cluster.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto clusters {Cluster::getAll(session)};
+		CHECK(clusters.size() == 1);
+		CHECK(clusters.front().id() == clusterId);
+		CHECK(clusters.front()->getType().id() == clusterTypeId);
+
+		auto clusterTypes {ClusterType::getAll(session)};
+		CHECK(clusterTypes.size() == 1);
+		CHECK(clusterTypes.front().id() == clusterTypeId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto cluster {Cluster::getById(session, clusterId)};
+		CHECK(cluster);
+		CHECK(cluster->getType().id() == clusterTypeId);
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+		CHECK(clusterType);
+
+		cluster.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleArtist(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType artistId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "dummy")};
+		CHECK(track);
+		auto artist {Artist::create(session, "dummy")};
+		CHECK(artist);
+
+		auto trackArtistLink {TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist)};
+
+		session.flush();
+		trackId = track.id();
+		artistId = artist.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		CHECK(track);
+
+		auto artists {track->getArtists()};
+		CHECK(artists.size() == 1);
+		auto artist {artists.front()};
+		CHECK(artist.id() == artistId);
+
+		CHECK(track->getArtistLinks().size() == 1);
+		auto artistLink {track->getArtistLinks().front()};
+		CHECK(artistLink->getTrack().id() == trackId);
+		CHECK(artistLink->getArtist().id() == artistId);
+
+		CHECK(track->getArtists(TrackArtistLink::Type::Artist).size() == 1);
+		CHECK(track->getArtists(TrackArtistLink::Type::ReleaseArtist).size() == 0);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		CHECK(artist);
+		auto tracks {artist->getTracks()};
+		CHECK(tracks.size() == 1);
+		auto track {tracks.front()};
+		CHECK(track.id() == trackId);
+
+		CHECK(artist->getTracks(TrackArtistLink::Type::ReleaseArtist).size() == 0);
+		CHECK(artist->getTracks(TrackArtistLink::Type::Artist).size() == 1);
+
+		track.remove();
+		artist.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleArtistMultiRoles(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType artistId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrack")};
+		auto artist {Artist::create(session, "MyArtist")};
+
+		TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist);
+		TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::ReleaseArtist);
+		TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Writer);
+
+		session.flush();
+		trackId = track.id();
+		artistId = artist.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		CHECK(track);
+
+		auto artists {track->getArtists(TrackArtistLink::Type::Artist)};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		artists = track->getArtists(TrackArtistLink::Type::ReleaseArtist);
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		CHECK(track->getArtistLinks().size() == 3);
+
+		auto artist {Artist::getById(session, artistId)};
+		CHECK(artist);
+		CHECK(artist->getTracks().size() == 1);
+		CHECK(artist->getTracks(TrackArtistLink::Type::ReleaseArtist).size() == 1);
+		CHECK(artist->getTracks(TrackArtistLink::Type::Artist).size() == 1);
+		CHECK(artist->getTracks(TrackArtistLink::Type::Writer).size() == 1);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		auto track {Track::getById(session, trackId)};
+
+		track.remove();
+		artist.remove();
+	}
+}
+
+static
+void
+testSingleTrackMultiArtists(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType artist1Id {};
+	IdType artist2Id {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "dummy")};
+		auto artist1 {Artist::create(session, "artist1")};
+		auto artist2 {Artist::create(session, "artist2")};
+
+		TrackArtistLink::create(session, track, artist1, TrackArtistLink::Type::Artist);
+		TrackArtistLink::create(session, track, artist2, TrackArtistLink::Type::Artist);
+
+		session.flush();
+		trackId = track.id();
+		artist1Id = artist1.id();
+		artist2Id = artist2.id();
+
+		CHECK(artist1Id != artist2Id);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		CHECK(track);
+
+		auto artists {track->getArtists()};
+		CHECK(artists.size() == 2);
+		CHECK((artists[0].id() == artist1Id && artists[1].id() == artist2Id)
+			|| (artists[0].id() == artist2Id && artists[1].id() == artist1Id));
+
+		CHECK(track->getArtists(TrackArtistLink::Type::Artist).size() == 2);
+		CHECK(track->getArtists(TrackArtistLink::Type::ReleaseArtist).size() == 0);
+		CHECK(Artist::getAll(session).size() == 2);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist1 {Artist::getById(session, artist1Id)};
+		CHECK(artist1);
+		auto tracks {artist1->getTracks()};
+		CHECK(tracks.size() == 1);
+		auto track {tracks.front()};
+		CHECK(track.id() == trackId);
+		auto artist2 {Artist::getById(session, artist2Id)};
+		CHECK(artist2);
+		CHECK(artist2->getTracks().front() == track);
+
+
+		CHECK(artist1->getTracks(TrackArtistLink::Type::ReleaseArtist).size() == 0);
+		CHECK(artist1->getTracks(TrackArtistLink::Type::Artist).size() == 1);
+		CHECK(artist2->getTracks(TrackArtistLink::Type::ReleaseArtist).size() == 0);
+		CHECK(artist2->getTracks(TrackArtistLink::Type::Artist).size() == 1);
+
+		track.remove();
+		artist1.remove();
+		artist2.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleRelease(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType releaseId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "dummy")};
+		CHECK(track);
+		auto release {Release::create(session, "dummy")};
+		CHECK(release);
+
+		track.modify()->setRelease(release);
+
+		session.flush();
+		trackId = track.id();
+		releaseId = release.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		CHECK(track);
+		CHECK(track->getRelease());
+		CHECK(track->getRelease().id() == releaseId);
+
+		auto release {Release::getById(session, releaseId)};
+		CHECK(release);
+		CHECK(release->getTracks().size() == 1);
+		CHECK(release->getTracks().front().id() == trackId);
+
+		track.remove();
+		release.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleCluster(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType clusterId {};
+	IdType clusterTypeId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "dummy")};
+		auto clusterType {ClusterType::create(session, "MyType")};
+		auto cluster {Cluster::create(session, clusterType, "MyCluster")};
+
+		cluster.modify()->addTrack(track);
+
+		session.flush();
+		trackId = track.id();
+		clusterTypeId = clusterType.id();
+		clusterId = cluster.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto tracks {Track::getByFilter(session, {clusterId})};
+		CHECK(tracks.size() == 1);
+		CHECK(tracks.front().id() == trackId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		auto cluster {Cluster::getById(session, clusterId)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		track.remove();
+		cluster.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleReleaseSingleCluster(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType releaseId {};
+	IdType clusterId {};
+	IdType clusterTypeId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrackFile")};
+		auto release {Release::create(session, "MyRelease")};
+		auto clusterType {ClusterType::create(session, "MyType")};
+		auto cluster {Cluster::create(session, clusterType, "MyCluster")};
+
+		track.modify()->setRelease(release);
+		cluster.modify()->addTrack(track);
+
+		session.flush();
+		trackId = track.id();
+		releaseId = release.id();
+		clusterTypeId = clusterType.id();
+		clusterId = cluster.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto releases {Release::getByFilter(session, {clusterId})};
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		auto release {Release::getById(session, releaseId)};
+		auto cluster {Cluster::getById(session, clusterId)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		track.remove();
+		release.remove();
+		cluster.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleArtistMultiClusters(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType artistId {};
+	IdType cluster1Id {};
+	IdType cluster2Id {};
+	IdType clusterTypeId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrackFile")};
+		auto artist {Artist::create(session, "MyArtist")};
+		auto clusterType {ClusterType::create(session, "MyType")};
+		auto cluster1 {Cluster::create(session, clusterType, "MyCluster1")};
+		auto cluster2 {Cluster::create(session, clusterType, "MyCluster2")};
+
+		auto trackArtistLink {TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist)};
+		cluster1.modify()->addTrack(track);
+
+		session.flush();
+		trackId = track.id();
+		artistId = artist.id();
+		clusterTypeId = clusterType.id();
+		cluster1Id = cluster1.id();
+		cluster2Id = cluster2.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artists {Artist::getByFilter(session, {cluster1Id})};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		artists = Artist::getByFilter(session, {cluster2Id});
+		CHECK(artists.size() == 0);
+
+		auto cluster2 {Cluster::getById(session, cluster2Id)};
+		auto track {Track::getById(session, trackId)};
+		cluster2.modify()->addTrack(track);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artists {Artist::getByFilter(session, {cluster1Id})};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		artists = Artist::getByFilter(session, {cluster2Id});
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		artists = Artist::getByFilter(session, {cluster1Id, cluster2Id});
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		auto artist {Artist::getById(session, artistId)};
+		auto cluster1 {Cluster::getById(session, cluster1Id)};
+		auto cluster2 {Cluster::getById(session, cluster2Id)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		track.remove();
+		artist.remove();
+		cluster1.remove();
+		cluster2.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleArtistMultiRolesMultiClusters(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType artistId {};
+	IdType clusterId {};
+	IdType clusterTypeId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrackFile")};
+		auto artist {Artist::create(session, "MyArtist")};
+		auto clusterType {ClusterType::create(session, "MyType")};
+		auto cluster {Cluster::create(session, clusterType, "MyCluster")};
+
+		TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist);
+		TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::ReleaseArtist);
+		cluster.modify()->addTrack(track);
+
+		session.flush();
+		trackId = track.id();
+		artistId = artist.id();
+		clusterTypeId = clusterType.id();
+		clusterId = cluster.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artists {Artist::getByFilter(session, {clusterId})};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::getById(session, trackId)};
+		auto artist {Artist::getById(session, artistId)};
+		auto cluster {Cluster::getById(session, clusterId)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		track.remove();
+		artist.remove();
+		cluster.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testMultiTracksSingleArtistMultiClusters(Wt::Dbo::Session& session)
+{
+	const std::size_t nbTracks {10};
+	const std::size_t nbClusters {5};
+	IdType artistId {};
+	IdType clusterTypeId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::create(session, "MyArtist")};
+
+		auto clusterType {ClusterType::create(session, "MyType")};
+		std::vector<Cluster::pointer> clusters;
+
+		for (std::size_t i {}; i < nbClusters; ++i)
+			clusters.push_back(Cluster::create(session, clusterType, "MyCluster" + std::to_string(i)));
+
+		for (std::size_t i {}; i < nbTracks; ++i)
+		{
+			auto track {Track::create(session, "MyTrackFile")};
+			TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist);
+
+			for (const auto& cluster : clusters)
+				cluster.modify()->addTrack(track);
+		}
+
+		session.flush();
+		artistId = artist.id();
+		clusterTypeId = clusterType.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		std::vector<Cluster::pointer> clusters {Cluster::getAll(session)};
+		CHECK(clusters.size() == nbClusters);
+
+		std::set<IdType> clusterIds;
+		std::transform(std::cbegin(clusters), std::cend(clusters), std::inserter(clusterIds, std::begin(clusterIds)), [](const Cluster::pointer& cluster) { return cluster.id(); });
+
+		auto artists {Artist::getByFilter(session, clusterIds)};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		std::vector<Cluster::pointer> clusters {Cluster::getAll(session)};
+		for (auto& cluster : clusters)
+			cluster.remove();
+
+		std::vector<Track::pointer> tracks {Track::getAll(session)};
+		for (auto& track : tracks)
+			track.remove();
+
+		auto artist {Artist::getById(session, artistId)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		artist.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleReleaseSingleArtist(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType releaseId {};
+	IdType artistId {};
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "dummy")};
+		auto release {Release::create(session, "dummy")};
+		auto artist {Artist::create(session, "dummy")};
+
+		auto trackArtistLink {TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist)};
+		track.modify()->setRelease(release);
+
+		session.flush();
+		trackId = track.id();
+		releaseId = release.id();
+		artistId = artist.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		CHECK(artist);
+		auto releases {artist->getReleases()};
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+
+		auto release {Release::getById(session, releaseId)};
+		CHECK(release);
+		auto artists {release->getArtists()};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		auto track {Track::getById(session, trackId)};
+
+		track.remove();
+		artist.remove();
+		release.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleReleaseSingleArtistSingleCluster(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType releaseId {};
+	IdType artistId {};
+	IdType clusterId {};
+	IdType clusterTypeId {};
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrackFile")};
+		auto release {Release::create(session, "MyRelease")};
+		auto artist {Artist::create(session, "MyArtist")};
+
+		auto clusterType {ClusterType::create(session, "MyType")};
+		auto cluster {Cluster::create(session, clusterType, "MyCluster")};
+
+		auto trackArtistLink {TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist)};
+		track.modify()->setRelease(release);
+		cluster.modify()->addTrack(track);
+
+		session.flush();
+		trackId = track.id();
+		releaseId = release.id();
+		artistId = artist.id();
+		clusterId = cluster.id();
+		clusterTypeId = clusterType.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artists {Artist::getByFilter(session, {clusterId})};
+		CHECK(artists.size() == 1);
+		CHECK(artists.front().id() == artistId);
+
+		auto artist {Artist::getById(session, artistId)};
+		auto releases {artist->getReleases()};
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+
+		releases = artist->getReleases({clusterId});
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		auto release {Release::getById(session, releaseId)};
+		auto track {Track::getById(session, trackId)};
+		auto cluster {Cluster::getById(session, clusterId)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		track.remove();
+		artist.remove();
+		release.remove();
+		cluster.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testSingleTrackSingleReleaseSingleArtistMultiClusters(Wt::Dbo::Session& session)
+{
+	IdType trackId {};
+	IdType releaseId {};
+	IdType artistId {};
+	IdType cluster1Id {};
+	IdType cluster2Id {};
+	IdType clusterTypeId {};
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto track {Track::create(session, "MyTrackFile")};
+		auto release {Release::create(session, "MyRelease")};
+		auto artist {Artist::create(session, "MyArtist")};
+
+		auto clusterType {ClusterType::create(session, "MyType")};
+		auto cluster1 {Cluster::create(session, clusterType, "MyCluster1")};
+		auto cluster2 {Cluster::create(session, clusterType, "MyCluster2")};
+
+		auto trackArtistLink {TrackArtistLink::create(session, track, artist, TrackArtistLink::Type::Artist)};
+		track.modify()->setRelease(release);
+		cluster1.modify()->addTrack(track);
+		cluster2.modify()->addTrack(track);
+
+		session.flush();
+		trackId = track.id();
+		releaseId = release.id();
+		artistId = artist.id();
+		cluster1Id = cluster1.id();
+		cluster2Id = cluster2.id();
+		clusterTypeId = clusterType.id();
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		auto releases {artist->getReleases()};
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+
+		releases = artist->getReleases({cluster1Id, cluster2Id});
+		CHECK(releases.size() == 1);
+		CHECK(releases.front().id() == releaseId);
+	}
+
+	{
+		Wt::Dbo::Transaction transaction {session};
+
+		auto artist {Artist::getById(session, artistId)};
+		auto release {Release::getById(session, releaseId)};
+		auto track {Track::getById(session, trackId)};
+		auto cluster1 {Cluster::getById(session, cluster1Id)};
+		auto cluster2 {Cluster::getById(session, cluster1Id)};
+		auto clusterType {ClusterType::getById(session, clusterTypeId)};
+
+		track.remove();
+		artist.remove();
+		release.remove();
+		cluster1.remove();
+		cluster2.remove();
+		clusterType.remove();
+	}
+}
+
+static
+void
+testDatabaseEmpty(Wt::Dbo::Session& session)
+{
+	Wt::Dbo::Transaction transaction {session};
+
+	CHECK(Artist::getAll(session).size() == 0);
+	CHECK(Cluster::getAll(session).size() == 0);
+	CHECK(ClusterType::getAll(session).size() == 0);
+	CHECK(Release::getAll(session).size() == 0);
+	CHECK(Track::getAll(session).size() == 0);
+}
+
+int main(int argc, char* argv[])
+{
+
+	try
+	{
+		boost::filesystem::path tmpFile {boost::filesystem::temp_directory_path() / boost::filesystem::unique_path()};
+		ScopedFileDeleter tmpFileDeleter {tmpFile};
+
+		std::cout << "Database test file: '" << tmpFile.string() << "'" << std::endl;
+
+		std::unique_ptr<Wt::Dbo::SqlConnectionPool> connectionPool{ Handler::createConnectionPool(tmpFile) };
+
+		Handler db {*connectionPool};
+		Wt::Dbo::Session& session {db.getSession()};
+
+		auto runTest = [&session](const std::string& name, std::function<void(Wt::Dbo::Session&)> testFunc)
+		{
+			std::cout << "Running test '" << name << "'..." << std::endl;
+			testFunc(session);
+			testDatabaseEmpty(session);
+			std::cout << "Running test '" << name << "': SUCCESS" << std::endl;
+		};
+
+#define RUN_TEST(test)	runTest(#test, test)
+
+		RUN_TEST(testSingleTrack);
+		RUN_TEST(testSingleArtist);
+		RUN_TEST(testSingleRelease);
+		RUN_TEST(testSingleCluster);
+
+		RUN_TEST(testSingleTrackSingleArtist);
+		RUN_TEST(testSingleTrackSingleArtistMultiRoles);
+		RUN_TEST(testSingleTrackMultiArtists);
+
+		RUN_TEST(testSingleTrackSingleRelease);
+
+		RUN_TEST(testSingleTrackSingleCluster);
+
+		RUN_TEST(testSingleTrackSingleReleaseSingleCluster);
+		RUN_TEST(testSingleTrackSingleArtistMultiClusters);
+		RUN_TEST(testSingleTrackSingleArtistMultiRolesMultiClusters);
+		RUN_TEST(testMultiTracksSingleArtistMultiClusters);
+
+		RUN_TEST(testSingleTrackSingleReleaseSingleArtist);
+
+		RUN_TEST(testSingleTrackSingleReleaseSingleArtistSingleCluster);
+		RUN_TEST(testSingleTrackSingleReleaseSingleArtistMultiClusters);
+
+	}
+	catch (std::exception& e)
+	{
+		std::cerr << "Caught exception: " << e.what() << std::endl;
+		return EXIT_FAILURE;
+	}
+
+	return EXIT_SUCCESS;
+}
diff --git a/test/som-test/SomTest.cpp b/test/som/SomTest.cpp
similarity index 76%
rename from test/som-test/SomTest.cpp
rename to test/som/SomTest.cpp
index 2c96f54e..f7572746 100644
--- a/test/som-test/SomTest.cpp
+++ b/test/som/SomTest.cpp
@@ -1,12 +1,29 @@
+/*
+ * Copyright (C) 2019 Emeric Poupon
+ *
+ * This file is part of LMS.
+ *
+ * LMS is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * LMS is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <sstream>
 #include <cassert>
-#include <assert.h>
 #include <iostream>
 
 #include "DataNormalizer.hpp"
 #include "Network.hpp"
 
-#define CHECK(pred)	assert((pred))
-
 using namespace SOM;
 
 int main(int argc, char* argv[])