Index: lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/learningdesign/Grouping.hbm.xml
===================================================================
diff -u -r8e764cef94c3501df91598521080a8bf2c5160b2 -rc0710880f1bac8ff501394218afacdb9286c5469
--- lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/learningdesign/Grouping.hbm.xml	(.../Grouping.hbm.xml)	(revision 8e764cef94c3501df91598521080a8bf2c5160b2)
+++ lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/learningdesign/Grouping.hbm.xml	(.../Grouping.hbm.xml)	(revision c0710880f1bac8ff501394218afacdb9286c5469)
@@ -73,22 +73,12 @@
     <subclass name="org.lamsfoundation.lams.learningdesign.ChosenGrouping" discriminator-value="2"/>
         
     <subclass name="org.lamsfoundation.lams.lesson.LessonClass" discriminator-value="3">
-        <!-- bi-directional many-to-one (effectiviey a  one to one) assocaites to Group in staff group role -->
+        <!-- uni-directional many-to-one (effectiviey a  one to one) assocaites to Group in staff group role -->
         <many-to-one name="staffGroup" class="org.lamsfoundation.lams.learningdesign.Group" column="staff_group_id" unique="true"/>
-         <!-- bi-directional one-to-many association to Lesson -->
-    <set
-        name="lesson"
-        lazy="true"
-        inverse="true"
-		cascade="none"
-    >
-        <key>
-            <column name="class_grouping_id" />
-        </key>
-        <one-to-many 
-            class="org.lamsfoundation.lams.lesson.Lesson"
-        />
-    </set>
+        <!-- bi-directional one-to-one association to Lesson -->
+        <one-to-one name="lesson"
+        	class="org.lamsfoundation.lams.lesson.Lesson"
+        	property-ref="lessonClass" />
     </subclass>
 </class>
 </hibernate-mapping>