Hibernate fetch strategy when using one table to inherit class hierarchy

Hi I am using a single table to match the inheritance of the class hierarchy for legacy data, as described here.

http://docs.jboss.org/hibernate/core/3.3/reference/en/html/inheritance.html#inheritance-tableperclass

this is what my display looks like

<class abstract="true" name="note" table="NOTES">
 <id name="id" type="long" column="NOTE_ID">
     <generator class="native"/>
 </id>
 <discriminator column="NOTE_TYPE" type="string"/>
 <property name="orderId" column="ORDER_ID"/>
 <property name="text" column="TEXT"/>
 <subclass name="PurchaseNote" discriminator-value="PUR" />
 <subclass name="CancelNote" discriminator-value="CAN" />
 <subclass name="RefundNote" discriminator-value="REF" />
</class>

For each order ID

Notes are described as associations in the order class, for example

<class name="order" table="ORDERS">
 <id name="id" type="long" column="ORDER_ID">
     <generator class="native"/>
 </id>
 .....
<set name="purchaseNotes">
    <key column="orderId" />
    <one-to-many class="PurchaseNote"/>
</set>
<set name="cancelNotes">
    <key column="orderId" />
    <one-to-many class="cancelNote"/>
</set>
<set name="refundNotes">
    <key column="orderId" />
    <one-to-many class="refundNote"/>
</set>

</class>

I can get related collections obtained using hibernate if I do the following.

1) Use the Where clause in the set definition in xml order or 2) Use force = "true" as part of the discriminator definition in xml notes

, DAO hibernate factory, HQL "from RefundNote, orderId =?" "from Note note note.class= RefundNote orderId =?" RefundNote Order, setter on refundNotes.

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