diff --git a/src/database/DbArtist.cpp b/src/database/DbArtist.cpp
index b9dfb1ed..87d90567 100644
--- a/src/database/DbArtist.cpp
+++ b/src/database/DbArtist.cpp
@@ -143,7 +143,7 @@ std::vector<Wt::Dbo::ptr<Release>>
 Artist::getReleases(const std::set<IdType>& clusterIds) const
 {
 	assert(self());
-	assert(self()->id() != Wt::Dbo::dbo_traits<Artist>::invalidId() );
+	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	WhereClause where;
@@ -188,7 +188,7 @@ std::vector<std::vector<Wt::Dbo::ptr<Cluster>>>
 Artist::getClusterGroups(std::vector<ClusterType::pointer> clusterTypes, std::size_t size) const
 {
 	assert(self());
-	assert(self()->id() != Wt::Dbo::dbo_traits<Artist>::invalidId() );
+	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	WhereClause where;
diff --git a/src/database/Playlist.cpp b/src/database/Playlist.cpp
index 0b52b86c..ca5cccd1 100644
--- a/src/database/Playlist.cpp
+++ b/src/database/Playlist.cpp
@@ -87,6 +87,7 @@ std::vector<Wt::Dbo::ptr<PlaylistEntry>>
 Playlist::getEntries(int offset, int size, bool& moreResults) const
 {
 	assert(session());
+	assert(IdIsValid(self()->id()));
 
 	moreResults = false;
 
diff --git a/src/database/Release.cpp b/src/database/Release.cpp
index d1a302dc..c5f610e9 100644
--- a/src/database/Release.cpp
+++ b/src/database/Release.cpp
@@ -166,7 +166,7 @@ std::vector<Wt::Dbo::ptr<Artist>>
 Release::getArtists() const
 {
 	assert(self());
-	assert(self()->id() != Wt::Dbo::dbo_traits<Release>::invalidId() );
+	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	Wt::Dbo::collection<Wt::Dbo::ptr<Artist>> res = session()->query<Wt::Dbo::ptr<Artist>>(
diff --git a/src/database/Track.cpp b/src/database/Track.cpp
index 6b553258..aeedf327 100644
--- a/src/database/Track.cpp
+++ b/src/database/Track.cpp
@@ -214,7 +214,7 @@ std::vector<std::vector<Cluster::pointer>>
 Track::getClusterGroups(std::vector<ClusterType::pointer> clusterTypes, std::size_t size) const
 {
 	assert(self());
-	assert(self()->id() != Wt::Dbo::dbo_traits<Artist>::invalidId() );
+	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	WhereClause where;
@@ -322,7 +322,7 @@ Cluster::pointer
 ClusterType::getCluster(std::string name) const
 {
 	assert(self());
-	assert(self()->id() != Wt::Dbo::dbo_traits<ClusterType>::invalidId() );
+	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	return session()->find<Cluster>()
@@ -334,7 +334,7 @@ std::vector<Cluster::pointer>
 ClusterType::getClusters() const
 {
 	assert(self());
-	assert(self()->id() != Wt::Dbo::dbo_traits<ClusterType>::invalidId() );
+	assert(IdIsValid(self()->id()));
 	assert(session());
 
 	Wt::Dbo::collection<Cluster::pointer> res = session()->find<Cluster>()
diff --git a/src/database/Track.hpp b/src/database/Track.hpp
index 9fc4f3a8..c367fc98 100644
--- a/src/database/Track.hpp
+++ b/src/database/Track.hpp
@@ -120,7 +120,7 @@ class ClusterType : public Wt::Dbo::Dbo<ClusterType>
 		Wt::Dbo::collection< Wt::Dbo::ptr<Cluster> > _clusters;
 };
 
-class Track : public Wt::Dbo::Dbo<Cluster>
+class Track : public Wt::Dbo::Dbo<Track>
 {
 	public:
 
diff --git a/src/database/Types.hpp b/src/database/Types.hpp
index 5aa1644f..2ff23abd 100644
--- a/src/database/Types.hpp
+++ b/src/database/Types.hpp
@@ -23,5 +23,10 @@
 
 namespace Database {
 	using IdType = Wt::Dbo::dbo_default_traits::IdType;
+
+	static inline bool IdIsValid(IdType id)
+	{
+		return id != Wt::Dbo::dbo_default_traits::invalidId();
+	}
 }
 
diff --git a/src/ui/explore/TracksView.cpp b/src/ui/explore/TracksView.cpp
index 5b7796e1..2d1d53ee 100644
--- a/src/ui/explore/TracksView.cpp
+++ b/src/ui/explore/TracksView.cpp
@@ -136,15 +136,13 @@ Tracks::addSome()
 
 		entry->bindString("name", Wt::WString::fromUTF8(track->getName()), Wt::TextFormat::Plain);
 
-		auto artist = track->getArtist();
-		if (artist)
+		if (track->getArtist())
 		{
 			entry->setCondition("if-has-artist", true);
 			entry->bindWidget("artist-name", LmsApplication::createArtistAnchor(track->getArtist()));
 		}
 
-		auto release = track->getRelease();
-		if (release)
+		if (track->getRelease())
 		{
 			entry->setCondition("if-has-release", true);
 			entry->bindWidget("release-name", LmsApplication::createReleaseAnchor(track->getRelease()));
@@ -157,7 +155,7 @@ Tracks::addSome()
 		Wt::WContainerWidget* clusterContainers = entry->bindNew<Wt::WContainerWidget>("clusters");
 		{
 			auto clusterTypes = getClusterTypesFromSetting(trackClusterTypesSetting);
-			auto clusterGroups = release->getClusterGroups(clusterTypes, 1);
+			auto clusterGroups = track->getClusterGroups(clusterTypes, 1);
 
 			for (auto clusters : clusterGroups)
 			{