diff --git a/navalplanner-business/src/main/resources/org/navalplanner/business/templates/entities/Templates.hbm.xml b/navalplanner-business/src/main/resources/org/navalplanner/business/templates/entities/Templates.hbm.xml
index 45faef7fd..bb22e0730 100644
--- a/navalplanner-business/src/main/resources/org/navalplanner/business/templates/entities/Templates.hbm.xml
+++ b/navalplanner-business/src/main/resources/org/navalplanner/business/templates/entities/Templates.hbm.xml
@@ -17,7 +17,7 @@
         <property name="startAsDaysFromBeginning" />
         <property name="deadlineAsDaysFromBeginning" />
 
-        <many-to-one name="parent" access="field" />
+        <many-to-one name="parent" access="field" class="org.navalplanner.business.templates.entities.OrderLineGroupTemplate"/>
 
         <set name="materialAssignments" cascade="all-delete-orphan" inverse="true">
             <key column="ORDER_ELEMENT_TEMPLATE_ID" not-null="true" />