Hi everybody.

I am having a problem while using many-to-many with a unique constraint (so that the collection acts as one-to-many).

I have three classes - Orderline, OrderLineId, and Order. The class Orderline has a composite id of type OrderLineId and is mapped in two tables i.e. ORDERLINE and LINKTABLE. The class Order has a unidirectional one-to-many association with the class Orderline.

Here is my mapping -
<hibernate-mapping>
<class name="Orderline" table="ORDERLINE">
<composite-id name="id" class="OrderLineId">
<key-property name="lineId" column="LINEID"/>
<key-property name="orderId" column="ORDERID"/>
<key-property name="customerId" column="CUSTOMERID"/>
</composite-id>
<property name="name" column="NAME"/>
<join table="LINKTABLE">
<key>
<column name="LINEID"/>
<column name="ORDER_ID"/>
<column name= "CUSTOMERID"/>
</key>
<property name="typename" column="TYPENAME"/>
</join>

</class>

<class name="Order" table="ORDERTABLE">
<id name="id" column="ORDER_ID" type="java.lang.Long">
<generator class="increment"/>
</id>
<property name="orderName" column="ORDER_NAME"/>
<set name="orderLines" table="LINKTABLE">
<key>
<column name="ORDER_ID"/>
</key>
<many-to-many class="Orderline" unique="true">
<column name= "LINED"/>
<column name= "ORDERID"/>
<column name= "CUSTOMERID"/>
</many-to-many>
</set>
</class>
</hibernate-mapping>

since I have a <join> tag, I am using many-to-many with a unique constraint. Am I supposed to add unique="true" in each column of a many-to-many tag?

Any help will be appreciated!!

Thank you.