I have a table "Questions" with a key formed by fields "id_question" and "id_prog_question" (a counter).
Each question may have a set of children questions, bounded to the parent question by a key formed by fields (parent_id,parent_prog). How can I model this set?

<class name="Questions" table="questions">
<composite-id name="id" class="QuestionsKey">
<key-property name="id_question" column="id_question" type="java.lang.Integer" />
<key-property name="id_prog_question" column="id_prog_question" type="java.lang.Integer" />
</composite-id>
...
<set name="childrenquestions" inverse="true" lazy="false">
<key column="parent_id" />
<key column="parent_prog" />
<one-to-many class="Questions" />
</set>
</class>

this doesnt work. Must I define a "ChildrenQuestionsKey" element containing the two fields parent_id and parent_prog? please help
thanks

Try:

it works! thank you