Hello,
With Weblogic unfortunately I'll only be able to test SQL Server/Sybase.I will be happy to do the test with Oracle as the underlying database if you want.
For CMP, the container should create and return the primary key during the ejbCreate invocation. Hence, you are right.I have to check the specs, but from what I recall from the EJB Books I've read, it seems like the proper place to insert to set/get the key is after ejbCreate but before ejbPostCreate... Am I wrong in this?
In the book "EJB Design Patterns", this design is named "Sequence Blocks". The described idea is to front an Entity Bean in charge of the generation of primary keys with a Session Bean, SequenceSessionBean, in charge of the caching of blocks of primary keys.I also have to think about, as Jeremy recommended, generic methodologies for Key Generation. As I see it there are two types of generation we should support - database managed, such as creating a generic sequence table or calling a key generation stored proc (there is a common one we use at work for Sybase, as before 12.5 [which we just upgraded to] there were issues with Identitys and key gap from what I'm told), and container managed - where we keep a keyset in memory and generate our own keys.
This approach has some drawbacks; however it is common whatever the underlying datastore.
Based on this idea, another implementation choice could be:
In the ejbCreate method generated by the container, one could invoke the SequenceSessionBean in order to get the next available primary key. The problem is that one needs to access SequenceSessionBean. It means that an ejb-local-ref needs to be defined in the DD, which is not really convenient. However, if one could export implicitely such a reference based on the custom DD, then this approach could be used and could potentially be more portable and generic.
Having not yet (I am late on this side) browse the source code of OpenEJB, I really do not know if it is feasable.
Cheers, Gianny
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