On Jun 7, 2007, at 3:32 AM, Andrus Adamchik wrote:
I'm kind of curious if Cayenne supports PK-less for read-only data now, though. Seems to me that could be a useful thing.It doesn't - otherwise you won't be able to build a valid ObjectId and hence - ensure uniqueness across the context.The only way we can potentially support it is by supporting "disconnected" objects, i.e. objects that are fetched from DB, but not registered in the ObjectContext. Such objects will only be marginally more useful than DataRows though. (IIRC JPA supports disconnected objects, produced in some other unrelated scenarios).
JPA supports disconnected objects, that were once retrieved from (or persisted in) the database. It doesn't support disconnected objects without a database identity.
Craig
Andrus On Jun 6, 2007, at 7:42 PM, Michael Gentry wrote:It's not a hijacking. It is interesting to point out that JPA does not support tables without PKs -- I really should learn more about JPA soon. I can understand why, too (need to know what to update and how to make joins, etc). I'm kind of curious if Cayenne supports PK-less for read- only datanow, though. Seems to me that could be a useful thing. /dev/mrg On 6/6/07, Craig L Russell <[EMAIL PROTECTED]> wrote:I don't want to hijack this thread, but just point out that JPA does not support tables without primary key; JDO does (including updates) as an optional feature. Craig
Craig Russell Architect, Sun Java Enterprise System http://java.sun.com/products/jdo 408 276-5638 mailto:[EMAIL PROTECTED] P.S. A good JDO? O, Gasp!
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