Some more infos. The behavious of DataNucleus depends on the strategy I choose to generate the @Id field.
When I use GAE I always use the GenerationType.IDENTITY because I read that on JDO docs (http://code.google.com/appengine/docs/java/datastore/ dataclasses.html: Primary keys of type Key require a @PrimaryKey annotation and a @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) annotation) and I saw that GAE documentation about JDO is usually more deep that JPA documentation. But If I choose GenerationType.AUTO then I see that also DataNucleus, like all the other persistence provider, generate the key after the persist and before the flush/commit. Very strange indeed because for H2 DataBase the AUTO should choose IDENTITY generation. I'm still more convinced this is a bug in DataNucleus that affect the way we work on Google App Engine. On 19 Mag, 07:26, datanucleus <andy_jeffer...@yahoo.com> wrote: > I've already asked you twice to post your class. You haven't. That > provides no context for any comment, and I've already told you why > datastore operations are delayed until commit/flush. Why do you think > there's a flush() method if you think things ought to go straight to > the datastore ? > > JPA2 spec page 29 footnote 12. > <spec>[12] If the application does not set the primary key attribute > corresponding to the relationship, the value of that attribute may not > be available until after the entity has been flushed to the database.</ > spec> > > <spec>/** > * Synchronize the persistence context to the underlying database. > * @throws PersistenceException if the flush fails > */ > public void flush();</spec> > > <spec>• If X is a new entity, it becomes managed. The entity X will be > entered into the database at or > before transaction commit or as a result of the flush operation.</ > spec> > > http://www.datanucleus.org/products/accessplatform/jpa/transaction_ty... > > End. > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine for Java" group. > To post to this group, send email to google-appengine-j...@googlegroups.com. > To unsubscribe from this group, send email to > google-appengine-java+unsubscr...@googlegroups.com. > For more options, visit this group > athttp://groups.google.com/group/google-appengine-java?hl=en. -- You received this message because you are subscribed to the Google Groups "Google App Engine for Java" group. To post to this group, send email to google-appengine-j...@googlegroups.com. To unsubscribe from this group, send email to google-appengine-java+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
