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Hibernate version: 3.0

Problem:
I have a many to many relationship between USER and ROLE. Please find below the mapping files for USER and ROLE.
I need to add additional columns(GROUP, APP_ID) to the association table USER_ROLE .
Is it possible to add above fields (GROUP, APP_ID) to the SET or BAG which has many-to-many?
If it is can any one provide an example of mapping and POJO.

Following the database tables:



USER
_____________

*UID
NAME
DOB
_____________
______________

USER_ROLE
__________________

*USER_UID
*ROLE_RID
__________________
GROUP
APP_ID
__________________

___________

ROLE
_____________


*RID
NAME
DESC

_____________



Following mappings and client works well without new fields (GROUP, APP_ID)..


user.hbm.xml
============
<hibernate-mapping>
.......

<set name="roleList" table="USER_ROLE">
<key column="UID"/>
<many-to-many column="RID" class="Role"/>
</set>

</hibernate-mapping>

User.java
=========

public class User {
..
...
...
private Set roleList = new HashSet();

public Set getRoleList() {
return roleList;
}

public void setRoleList(Set roleList) {
roleList = roleList;
}

.....
.....
}


TestClient.java
===============
public class TestClient {
........
........
User user = (User) session.load(User.class, userId);
Role role = (Role) session.load(Role.class, roleId);

user.getRoleList().add(role);

.........
.......

}

Name and version of the database you are using: Oracle 9i








Problems with Session and transaction handling?

Read this: http://hibernate.org/42.html[/img]

You have two options:

1) An intermediate Entity Class for the join table with one-to-many mappings


2) Using a collection of components which is described here:
http://www.hibernate.org/hib_docs/v3/re ... ollections
You should be aware that bidirectional navigation is NOT supported with this approach.
This mapping is copy pasted from the Hibernate documentation, I have just marked the interesting part of this kind of mapping.

<class name="eg.Order" .... >
....
<set name="purchasedItems" table="purchase_items" lazy="true">
<key column="order_id">
<composite-element class="eg.Purchase">
<property name="purchaseDate"/>
<property name="price"/>
<property name="quantity"/>
<many-to-one name="item" class="eg.Item"/>
</composite-element>
</set>
</class>

Thank you for the reply.

Actually I tried this even before posting the message.

Here is the mapping I had:

<bag name="roleList" table="USER_ROLE" cascade="save-update" lazy="false">
<key column="UID" />

<composite-element class="UserRole">
<property name="group" column="GROUP" type="string"/>
<property name="appId" column="APP_ID" type="integer"/>

<many-to-one name="role" class="Role"/>
</composite-element>

</bag>

This produces following error:
Could not find a getter for role in class UserRole.java

I guess I need help in writing the UserRole.java. Also, I am worried about how Hibernate saves the data, I mean the order of ID creation and usage.
Can you provide a sample code segment.

This is straight forward, it is a usual POJO with getters and setters for it's properties.