See my comments inline On Wed, Sep 26, 2012 at 10:05 PM, Brian Topping <[email protected]> wrote: > Dan, I went through a lot of this recently with OpenJPA. YMMV with other > providers.
Brian, thank you for sharing this experience, it is surely settle our headache a bit!! > > 1. OpenJPA doesn't seem to manage very well with base classes across bundle > boundaries. It looked like there needed to be more magic in place that it > could deal with not being able to enhance or otherwise modify the superclass > jar due to classloader isolation. I did set up build time enhancement but it > didn't seem to be enough and I forgot where I was in the code that it was a > problem. One solution to this *may* be to use fragment hosts. For now, > we've just duplicated the base classes across the persistence bundles, > kicking the can down the road a bit. > This would mean all your duplicate base classes have their own java package to prevent collision? > 2. I have been successful in having multiple persistence units in the same > Karaf runtime and sharing a single data source, but the PUs do need to be > named differently. We have noticed some race conditions that occur, turning > on JPA logging seems to bury them a little deeper, and we haven't had time to > explore what's going on so we can report it. This is worry some. Are you able to bring your JPA into production with this issue? > > 3. One of the issues with multiple PUs is you need to set them up with > different names for the sequence tables under DBs like Postgres and Oracle. > This can be done statically from persistence.xml. > > I'm very interested in resolutions to these issues and would like to > contribute to them, but have been under a lot of pressure with client > deadlines. I wonder if others have seen any of these issues yet and can > offer any better advice than this. > > Cheers, B Thanks -D > > On Sep 26, 2012, at 9:01 PM, Dan Tran <[email protected]> wrote: > >> Hi, >> >> I am porting a set of JPA moduels under spring to Karaf JPA where I >> have i module which contains abstract entity classes, and a couple of >> other JPA modules use the 'base module', is it possible under >> jpa/openjpa/derby?? >> >> I am struggling on what do do with the base module since it has no >> entities, what the persistent.xml looks like, should it has its own >> persistent unit? >> >> Can all three modules use the same persistent unit name? >> >> any suggestion is greatly appreciated. >> >> thanks >> >> -D >
