Hibernate version: 3
Mapping documents: N/A
Code between sessionFactory.openSession() and session.close(): N/A
Full stack trace of any exception that occurs: N/A
Name and version of the database you are using: Any
The generated SQL (show_sql=true): N/A
Debug level Hibernate log excerpt: N/A


Hi,

I am trying to achieve something quite specific in a mapping but don't manage to do it...

I have 2 tables, ASSEMBLY_MASTER and ASSEMBLY_ITERATION.
I want to extract a single entity : Assembly from both Tables.
The hard point comes from the fact that the ASSEMBLY_MASTER row will be shared by several rows in the ASSEMBLY_ITERATION.

ASSEMBLY_MASTER have a generated Id as PK
ASSEMBLY_ITERATION uses a composite key based on the ASSEMBLY_MASTER ID and on a version number.

I ended up with the following mapping:

<hibernate-mapping package="cimpa.design2x.domain.model.to">
<class name="Assembly" table="ASSEMBLY_MASTER">
<id name="id" column="ASSEMBLY_ID">
<generator class="native"></generator>
</id>
<property name="name" column="NAME" type="string"></property>
<join table="ASSEMBLY_ITERATION">
<key>
<column name="ASSEMBLY_ID"></column>
</key>
<composite-id>
<column name="ASSEMBLY_ID"></column>
<column name="VERSION"></column>
</composite-id>
<property name="version" type="long" column="VERSION"></property>
</join>
</class>
</hibernate-mapping>

Surely this mapping is not valid but it represents well what I'm trying to achieve.

The target is to be able to retrieve a given version of an Assembly entity and to be able to create a new version of the assembly while altering the field held by the already existing master part...


Thanks for any help...

1st, you're posting a non-annotations-related question to wrong forum :) But you're mapping is very close to what you need. One thing you need to keep in mind that Hibernate does not need to emulate exactly what the database does. Just because the database defines a composite PK, doesn't mean your Object model needs one as well.

Since you can't have 2 IDs in a mapping file, as that is invalid, you obviously need to make sure those values are stored when you create or update the entity. You can however treat VERSION column a non-null property of your entity, even though the database sees it as part of the PK on the ASSEMBLY_ITERATION table. The mapping for ASSEMBLY_ID is already there due to the <key> element on the <join>. If you do that, it should work.

Ryan-