diff --git a/app/repositories/orient_db/learning_object/relation.rb b/app/repositories/orient_db/learning_object/relation.rb
index 066eabf834914a88e0189307a93bc1020f168887..f56115f8376769293f9a8cda26c5d00be323b3f6 100644
--- a/app/repositories/orient_db/learning_object/relation.rb
+++ b/app/repositories/orient_db/learning_object/relation.rb
@@ -1,6 +1,6 @@
 module OrientDb
   module LearningObject
-    class Relation
+    class Relation < OrientDb::Relation
       include OrientDb::Methods::EdgeMethods
 
       def initialize(learning_object)
diff --git a/app/repositories/orient_db/learning_object/relations_chain.rb b/app/repositories/orient_db/learning_object/relations_chain.rb
index bb3b59de373fc22e55d12f2dbaf42f0ce1a12fac..c5aa198dd9c3e343ebbe31075416f26649282c02 100644
--- a/app/repositories/orient_db/learning_object/relations_chain.rb
+++ b/app/repositories/orient_db/learning_object/relations_chain.rb
@@ -1,6 +1,6 @@
 module OrientDb
   module LearningObject
-    class RelationsChain
+    class RelationsChain < OrientDb::RelationChain
 
       def relations
         [
diff --git a/app/repositories/orient_db/subject/relation.rb b/app/repositories/orient_db/subject/relation.rb
index 926e65c30e7c0ceeb8f862a99a2ab2c9f35860a5..df88a69c76714eadcaf609221966f0a6632e8758 100644
--- a/app/repositories/orient_db/subject/relation.rb
+++ b/app/repositories/orient_db/subject/relation.rb
@@ -1,6 +1,6 @@
 module OrientDb
   module Subject
-    class Relation
+    class Relation < OrientDb::Relation
       include OrientDb::Methods::EdgeMethods
 
       def initialize(subject)
diff --git a/app/repositories/orient_db/subject/relations_chain.rb b/app/repositories/orient_db/subject/relations_chain.rb
index 7b99aa39b9153b5cc956781c4b9dc0ce4e49a418..3ef3ba941ec1076d717a2f86c0fa11c4525bcd32 100644
--- a/app/repositories/orient_db/subject/relations_chain.rb
+++ b/app/repositories/orient_db/subject/relations_chain.rb
@@ -1,6 +1,6 @@
 module OrientDb
   module Subject
-    class RelationsChain
+    class RelationsChain < OrientDb::RelationChain
 
       def relations
         [