diff --git a/library/Icingadb/Model/NotesUrl.php b/library/Icingadb/Model/NotesUrl.php
index 81c77e15..bd313a7e 100644
--- a/library/Icingadb/Model/NotesUrl.php
+++ b/library/Icingadb/Model/NotesUrl.php
@@ -32,6 +32,8 @@ class NotesUrl extends Model
         $relations->hasMany('host', Host::class)
             ->setCandidateKey('id')
             ->setForeignKey('notes_url_id');
-        $relations->hasMany('service', Service::class);
+        $relations->hasMany('service', Service::class)
+            ->setCandidateKey('id')
+            ->setForeignKey('notes_url_id');
     }
 }
diff --git a/library/Icingadb/Model/Service.php b/library/Icingadb/Model/Service.php
index f1d27adc..ece2cd13 100644
--- a/library/Icingadb/Model/Service.php
+++ b/library/Icingadb/Model/Service.php
@@ -92,7 +92,9 @@ class Service extends Model
         $relations->belongsTo('action_url', ActionUrl::class)
             ->setCandidateKey('action_url_id')
             ->setForeignKey('id');
-        $relations->belongsTo('notes_url', NotesUrl::class);
+        $relations->belongsTo('notes_url', NotesUrl::class)
+            ->setCandidateKey('notes_url_id')
+            ->setForeignKey('id');
         $relations->belongsTo('icon_image', IconImage::class);
         $relations->belongsTo('zone', Zone::class);
         $relations->belongsTo('endpoint', Endpoint::class)