many to many association without PK

irgeorgiev · **Joined:** Sat Sep 26, 2009 5:18 am **Posts:** 3

Hi

I have a object Node with :
class Node {
private int id // PK
private int objId
..... other properties
}

and object Element with:

class Element {
private int id // PK
private int nodeObjId
........ other properties
}

and i try to create many-to-many relation between them by objId and nodeObjId.

Do you have any idea ?

mumbaimuru · **Posted:** Tue Sep 29, 2009 5:53 am

Create reference(foreign key) in both classes and try.

mumbaimuru · **Posted:** Tue Sep 29, 2009 5:54 am

refer this...

Code:

<!-- bi-directional many-to-many association to Department -->
<set name="departments" table="employees_departments" inverse="true" cascade="all">
   <key column="employee_id"/>
   <many-to-many column="department_id" class="com.warfrog.hibernatetutorial2.hibernate.Department"/>
</set>

Now open Department and repeat the procedure pasting this code instead:

Code:

<!-- bi-directional many-to-many association to Employee -->
<set name="employees" table="employees_departments" cascade="all">
   <key column="department_id"/>
   <many-to-many column="employee_id" class="com.warfrog.hibernatetutorial2.hibernate.Employee"/>
</set>

tarun walia · **Joined:** Sat Aug 01, 2009 5:28 am **Posts:** 42

use join table,

http://docs.jboss.org/hibernate/core/3. ... ional-join

this link may help you

irgeorgiev · **Joined:** Sat Sep 26, 2009 5:18 am **Posts:** 3

thank you for your answers, but i found a solution.

The idea to create many-to-many association between these objects was wrong.

in class Node :

Code:

<set name="elements" table="elements" cascade="all">
   <key column="node_obj_id" property-ref="objId" />
   <one-to-many class="com.Element"/>
</set>

and the solution is to use column and property-ref in the same time