Could you please help me. I'v two clacess:
...
<hibernate-mapping>
<class
name="by.belsoft.tts.core.model.project.ProjectUser"
table="tts_project_user"
lazy="false"
>
<composite-id>

<key-property
name="portalUserId"
column="portal_user_ID"
length="255"
type="java.lang.String"
/>

<key-many-to-one
name="project"
class="by.belsoft.tts.core.model.project.Project"
column="project_ID"
/>
</composite-id>
</class>
</hibernate-mapping>

and:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd" >

<hibernate-mapping>
<class
name="by.belsoft.tts.core.model.project.Project"
table="tts_project"
lazy="false"
>
<id
name="projectId"
type="java.lang.Integer"
column="project_ID"
>
<generator class="increment" />
</id>
<!--
... properties
-->
<set
name="projectUsers"
lazy="false"
inverse="true"
cascade="all-delete-orphan"
>
<key
on-delete="cascade"
not-null="true"
column="project_ID"
/>
<one-to-many
class="by.belsoft.tts.core.model.project.ProjectUser"/>
</set>
<!--
...
-->

I know about the http://www.hibernate.org/hib_docs/refer ... -onetomany.
And I'v the following proplem:
while I try to update the Project with set of ProjectUsers I have the following:
nested exception is org.springframework.dao.DataIntegrityViolationException: (Hibernate operation: Could not execute JDBC batch update): data integrity violated by SQL 'insert into tts_project_user (portal_user_ID, project_ID) values (?, ?)'; nested exception is java.sql.BatchUpdateException: Column 'portal_user_ID' cannot be null

The equals and hashCode were tested and the ProjectUser class is serializabled.

I have been struggling with a very similar problem. From what I've been able to gather from the reference documentation - for the one-to-many set you have to use inverse=true, which it appears you have. The next piece of the puzzle which it looks like you may be missing is that the you have to have not-null="true" for the many-to-one for the project_id column. Apparently this lets hibernate know how to handle the processing of the 'child' entity in the join table.

How can I set the atribute not-null="true" in many-to-one association if the association is key-many-to-one? :)
As I see the key is not-null by default. But such association doesn't work. Moreover, the object retriving work properly, but object saving doesn,t.

Hi

I had problems with set How about a bag?

<bag name="projectUsers" lazy="false" inverse="true" cascade="all-delete-orphan" >
<key column="project_ID"></key>
<one-to-many class="by.belsoft.tts.core.model.project.ProjectUser"/>
</bag>

What are you speaking about?

In my case the set is the best solution. And I have tested with <bag/> - the issue still same. The pairs in ProjectUser (project_ID and project_user_ID) should be unique.

Is it really none know about the problem?

Unfortunately I'm going to realize this http://www.hibernate.org/117.html#A34

I have tried the following:
http://www.hibernate.org/117.html#A34
but the result still same. I expect that I have an error in the mapping.
Please, advice.

Reread Chapter 6:

As you can see:
<set
name="projectUsers"
lazy="false"
inverse="true"
cascade="all-delete-orphan"
>
<key
on-delete="cascade"
not-null="true"
column="project_ID"
/>
<one-to-many
class="by.belsoft.tts.core.model.project.ProjectUser"/>
</set>

Sorry, must have looked with "the white part of the eyes" ;-)

The problem was described also at:
http://www.guj.com.br/posts/list/32719.java
Unfortunately there is no answer in this forum.

I'h solved the problem throught:
http://www.hibernate.org/117.html#A34
and using pure update only. Whithount any preload and merge - this ways don't work.