On Fri, Oct 23, 2009 at 6:06 PM, datanucleus <andy_jeffer...@yahoo.com>wrote:
> > > * Transactions in JDO is a global thing tied to the persistence store > > (one database = one transaction), but for GAE it's one transaction per > > entity group. It's perfectly reasonable to execute two transactions at > > the same time, which is hard to fit into the traditional development > > model with spring. > > One txn per PM, at any one time. You can have multiple PMs open, hence > multiple txns. How Spring handles that is for Spring. > Injecting one PM per transaction seems cumbersome to me. It's also not documented anywhere AFAIK (at least, not in the transactions page). > > > * The current way of generating a primary key with a parent is not > > natural IMHO. My key attribute already has a parent, why should I add > > _another_ attribute with the parent PK? > > That is the problem of Google for exposing their Key. A user doesn't > care about internal handling. When we provided support for db4o we > didn't expose db4o's key, instead providing a clean long/String/int > type etc, and doing conversions internally ... aka transparent ... the > whole point of JDO. > I would say that AppEngine users care a big deal about the internals, specially when considering sharding. I understand that Google low-level interface does not fit well with JDO key conversion, but again that is my whole point - that maybe the standard is not the best option for this concrete case. > Please do continue the list, because I'm sure Max et al will be > interested to know what you think are problem areas so they can cater > for such things in their DN plugin. > Now that we are discussing it, I am curious: why does datanucleus only support owned relationships? There is not that much difference between the typical Foreign Key field and a GAE Key property. The fact is that the GAE/J DN plugin is > open source too, and Max et al are open to input on it > I am really grateful for all the insight about the subject. Thanks. --~--~---------~--~----~------------~-------~--~----~ 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-java@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 -~----------~----~----~----~------~----~------~--~---
