Re: [eclipselink-users] Merged entity question

[bea <beaotx@xxxxxxxxx>]

Hi,

Thank you for the resonse. I supposed that I'll do a manual merge.
I've seen the fetchGroup feature, I didn't know it. Would it be
possible to use it? I've seen its use in order to do queries, but I
don't see its applicability to my purpose.

Thanks again.


On Thu, Sep 3, 2009 at 5:10 PM, James Sutherland<jamesssss@xxxxxxxxx> wrote:
>
> Merge does not know what you changed in the clone, so must merge everything.
>
> If yes access the EclipseLink UnitOfWork from the EntityManager there are
> more merge options (shallow, deep), but if you wish to pick and choose what
> you merge, you are probably better off doing a manual merge of your objects
> in your own code.  A merge that takes an original state object may be
> useful, you might want to log an enhancement request for this.  One advanced
> mechanism to do this might be to set the object's fetchGroup.
>
>
> bea-5 wrote:
>>
>> Hi,
>>
>> I'm using eclipselink with JPA in order to manage some entities.
>> Right now I've one entity called Operator with an attribute called
>> Contacts, that is a relation-ship one-to-many to other table, with a
>> cascade type ALL.
>>
>> Some times I update the Operator and the nested Contacts with the
>> merge method. I've one question:
>>
>> If I've an entity of the database persisted, and I've a new entity
>> with the same ID than the one persisted but some data modified, could
>> I merge the second entity with the first one with a simple merge
>> method? If I do that all the old data not represented in the new
>> entity is removed.
>>
>> For example, imagine that newEntity is a new entity not managed but
>> with an id attribute existing in DB. If I type:
>>
>> Operator entity = em.merge(newEntity);
>>
>> entity has the values of newEntity. I'd like a mix between both
>> entities: the previous persisted and the new values from the new
>> entity.
>>
>> Thanks.
>>
>>
>
>
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