select a subset of object attributes

[reto <re...@yahoo.com>]

Hi togheter,

I want to retrieve only a subset of the attributes of an object (not retrieving
the blobs in the object). I use the PersistenceBroker API. Can anybody give me a
hint if that's possible without going back and using sql direct?
thanks reto


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Re: select a subset of object attributes

[Armin Waibel <ar...@apache.org>]

Hi,

reto wrote:

> Hi togheter,
> 
> I want to retrieve only a subset of the attributes of an object (not retrieving
> the blobs in the object). I use the PersistenceBroker API. Can anybody give me a
> hint if that's possible without going back and using sql direct?
> thanks reto
> 

- you can use Report Queries to retrieve a subset based on object value 
arrays.
http://db.apache.org/ojb/query.html#report%20queries
(Maven has corrupt this section, please use your local docs, call "ant 
htmldoc" to generate)
- Or you can declare two classes/class-descriptors with and without the 
Blob field.
- Or you "roll out" the blob fields in  a new class and use a 1:1 reference.
- Or you can use metadata profiles on a per thread basis. This allows 
you to change metadata at runtime (see javadoc of MetadataManager, 
recommended only for expert user, because you have to take care of cache)

regards,
Armin

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