Hi Tal, Tal Yalon wrote:
Hi,We're currently reviewing O/R mapping tools. Since the JDO and OTM implementations are not yet fully functional, and ODMG doesn't provide us with the necessary flexibility, we are primarily interested in the Persistence Broker API. I took a look and have some questions: - Does PB has JTA support,
yes! and if so how (I saw a combination of OTM/ODMG/PB
classes that put together may provide this functionality - but it's just a
guess)?
- Does PB supports distributed transactions?
no.
Can we not perform DB commit?
you can.
- We want to be able to catch OptimisticLock exceptions in our code before commiting. Can we flush all changes to the DB WITHOUT committing (and thus trigger OptimisticLock exceptions)?
you can. PB provides OL support
- Is the cache transcational (does it discard all changes made to objects in a rolled-back transaction)?
The cache is not transactional. But you can clear cache explicitely
- Can we do read-optimistic locking to avoid stale reads (i.e. doing a null UPDATE just to make sure the version hasn't changed)?
yes.
- Can we map the same fields to different objects (and how does the cache behave if it's possible)?
yes you can. Does not affect the cache.
yes, the mapping is done in meta-data layer that can be manipulated through a simple Meta object protocal at runtime.- Can we map an object using several mappings and switch them at runtime (i.e. moving an object from one table to another when its state changes)?
should not affect the cache.- How all these subjects affect the cache?
The cache is pluggable and can be easily replaced with user defined versions that implement special behaviour if needed.
cheers,
Thomas
Any help would be appreciated. Regards, Tal -- To unsubscribe, e-mail: <mailto:[EMAIL PROTECTED]> For additional commands, e-mail: <mailto:[EMAIL PROTECTED]>
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