Index: lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/learningdesign/Grouping.hbm.xml
===================================================================
diff -u -r8756278b764fa9a27108c99d0e7a501c84ca884f -re840fc03d3eb7ae1a3757be5ee65415caea89981
--- lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/learningdesign/Grouping.hbm.xml	(.../Grouping.hbm.xml)	(revision 8756278b764fa9a27108c99d0e7a501c84ca884f)
+++ lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/learningdesign/Grouping.hbm.xml	(.../Grouping.hbm.xml)	(revision e840fc03d3eb7ae1a3757be5ee65415caea89981)
@@ -73,10 +73,11 @@
     <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 -->
         <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
+        <one-to-one name="lesson"
+        	class="org.lamsfoundation.lams.lesson.Lesson"
+        	property-ref="lessonClass" />
+    <!-- set
         name="lessons"
         lazy="true"
         inverse="true"
@@ -88,7 +89,7 @@
         <one-to-many 
             class="org.lamsfoundation.lams.lesson.Lesson"
         />
-    </set>
+    </set-->
     </subclass>
 </class>
 </hibernate-mapping>
Index: lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/lesson/Lesson.hbm.xml
===================================================================
diff -u -raa94cd10d358b4a0f36be5d5f77a1edc3f0c61d1 -re840fc03d3eb7ae1a3757be5ee65415caea89981
--- lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/lesson/Lesson.hbm.xml	(.../Lesson.hbm.xml)	(revision aa94cd10d358b4a0f36be5d5f77a1edc3f0c61d1)
+++ lams_common/conf/hibernate/mappings/org/lamsfoundation/lams/lesson/Lesson.hbm.xml	(.../Lesson.hbm.xml)	(revision e840fc03d3eb7ae1a3757be5ee65415caea89981)
@@ -72,9 +72,12 @@
 		<!-- one-to-one name="lessonClass"
 			class="org.lamsfoundation.lams.lesson.LessonClass"
 			constrained="true"
-			cascade="all"
-			property-ref="lesson"
+			foreign-key="class_grouping_id"
 			/-->
+		<many-to-one name="lessonClass"
+			class="org.lamsfoundation.lams.lesson.LessonClass"
+			column="class_grouping_id"
+			unique="true" />
 
 		<!-- bi-directional many-to-one association to Organisation -->
 		<many-to-one name="organisation"