diff --git a/maloja/database/associated.py b/maloja/database/associated.py
index f486cef..d3f233d 100644
--- a/maloja/database/associated.py
+++ b/maloja/database/associated.py
@@ -27,7 +27,7 @@ def load_associated_rules():
 
 	# write to db
 	ops = [
-		sqldb.DB['associated_artists'].insert().values(**r)
+		sqldb.DB['associated_artists'].insert().values(**r).prefix_with('OR IGNORE')
 		for r in rules
 	]
 
diff --git a/maloja/database/sqldb.py b/maloja/database/sqldb.py
index b3817d2..c961e28 100644
--- a/maloja/database/sqldb.py
+++ b/maloja/database/sqldb.py
@@ -47,7 +47,8 @@ DB['trackartists'] = sql.Table(
 DB['associated_artists'] = sql.Table(
 	'associated_artists', meta,
 	sql.Column('source_artist',sql.Integer,sql.ForeignKey('artists.id')),
-	sql.Column('target_artist',sql.Integer,sql.ForeignKey('artists.id'))
+	sql.Column('target_artist',sql.Integer,sql.ForeignKey('artists.id')),
+	sql.UniqueConstraint('source_artist', 'target_artist')
 )
 
 meta.create_all(engine)