Disable ID generation for entity beans temporarily ?

[horst21]

Hello,

I have persistent ejb3 entity beans with an autogenerated id (@GeneratedValue(strategy = GenerationType.AUTO).

Is it possible to disable the id generation of these entity beans for a EntityManager.merge(..) or EntityManager.persist(..) call?

Does anybody have an idea if and how that could work? Maybe I could access and temporarily update the persistence-meta-data?

I think I need this in order to be able to import an existing object-graph with many relations and thus many foreign keys.
Of course another option would be to manually update the foreign keys with the new ids, but that seems pretty complex to implement and maintain.

Thanks for your help,
Tobias.

[wolfgangknauf]

Hi Tobias,

you could try to override the annotations with a deployment descriptor (orm.xml) and remove bold "generated value" attribute.

<entity class="..." metadata-complete="true">
 <table name="..."></table>
 <attributes>
 <id name="id">
 <column name="ID" />
 <generated-value/>
 </id>
 <basic name="...">
 <column name="..." />
 </basic>
 </attributes>
 </entity>

[horst21]

yes, I think using a deployment descriptor might work for me, thanks for the tip!

but I do not know what a "orm.xml" file is. Do you mean "hbm.xml"? Or do you mean the the "ejb-jar.xml" deployment descriptor?
When searching the web for documentation about it, I could not find any. Do you know if there is documentation about this, and where it I can find it?

Thanks a lot, Tobias.

[wolfgangknauf]

Hi Tobias,

"orm.xml" is new in EJB3, and it describes how the bean is mapped to the database (e.g. table names, column names, datatypes, just everything which can b declared with annotations).

If you read the EJB book by Monson-Haefel/Burke you will find some information about it.

Or you start by digging around the ejb specifiation: http://jcp.org/aboutJava/communityprocess/final/jsr220/index.html (take a look at the PDF labeled "JSR-000220 Enterprise JavaBeans 3.0 Final Release (persistence)").

Hope this helps

Wolfgang

[horst21]

Hi Wolfgang,

reading the ejb-spec lead the way ;-), I can disable ID-generation through the orm.xml now.
thank you very much for your help,

Tobias.