diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedDayAssignment.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedDayAssignment.java
index 249ecb983..8767326bb 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedDayAssignment.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/DerivedDayAssignment.java
@@ -38,6 +38,12 @@ public class DerivedDayAssignment extends DayAssignment {
                 derivedAllocation));
     }
 
+    /**
+     * Constructor for Hibernate. DO NOT USE!
+     */
+    public DerivedDayAssignment() {
+    }
+
     @NotNull
     private DerivedAllocation allocation;
 
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
index 1a710792e..5745a8d8f 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
@@ -26,8 +26,10 @@ import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 import java.util.Map.Entry;
 
 import org.apache.commons.lang.Validate;
@@ -241,6 +243,8 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
     @NotNull
     private ResourcesPerDay resourcesPerDay;
 
+    private Set<DerivedAllocation> derivedAllocations = new HashSet<DerivedAllocation>();
+
     /**
      * Constructor for hibernate. Do not use!
      */
diff --git a/navalplanner-business/src/main/resources/org/navalplanner/business/planner/entities/ResourceAllocations.hbm.xml b/navalplanner-business/src/main/resources/org/navalplanner/business/planner/entities/ResourceAllocations.hbm.xml
index ae47855c6..57bbce33d 100644
--- a/navalplanner-business/src/main/resources/org/navalplanner/business/planner/entities/ResourceAllocations.hbm.xml
+++ b/navalplanner-business/src/main/resources/org/navalplanner/business/planner/entities/ResourceAllocations.hbm.xml
@@ -20,6 +20,11 @@
             column="ASSIGNMENT_FUNCTION" not-null="false"
             cascade="all" lazy="false" />
 
+        <set name="derivedAllocations" cascade="all" inverse="true">
+            <key column="RESOURCE_ALLOCATION_ID" />
+            <one-to-many class="DerivedAllocation"/>
+        </set>
+
         <joined-subclass name="SpecificResourceAllocation" table="specific_resource_allocation">
             <key column="RESOURCE_ALLOCATION_ID" />
 
@@ -78,6 +83,9 @@
             <many-to-one name="genericResourceAllocation"
                 class="GenericResourceAllocation" column="GENERIC_RESOURCE_ALLOCATION_ID" />
         </subclass>
+        <subclass name="DerivedDayAssignment" discriminator-value="DERIVED_DAY">
+            <many-to-one name="allocation" column="DERIVED_ALLOCATION_ID"/>
+        </subclass>
     </class>
 
     <!-- AssignmentFunction -->
@@ -107,4 +115,20 @@
 
     </class>
 
+    <class name="DerivedAllocation">
+        <id name="id" type="long" access="property" >
+	        <generator class="hilo">
+	            <param name="max_lo">100</param>
+	        </generator>
+        </id>
+        <version name="version" access="property" type="long" />
+        <many-to-one class="ResourceAllocation" column="RESOURCE_ALLOCATION_ID"
+                     name="derivedFrom" not-null="true" />
+        <many-to-one class="org.navalplanner.business.resources.entities.MachineWorkersConfigurationUnit"
+            name="configurationUnit" not-null="true"/>
+        <set name="assignments" cascade="all" inverse="true">
+            <key column="DERIVED_ALLOCATION_ID"/>
+            <one-to-many class="DerivedDayAssignment"/>
+        </set>
+    </class>
 </hibernate-mapping>