[appengine-java] Re: Disappointment about JPA relationships :(
That is very true. The page you show is quite explaining why i got theses exceptions, but i wouldn't have understood anything before i ran into theses exceptions, and not even understanding if this page was JDO or JPA documentation. Anyway, i got it now and i'm back on tracks, but i would have gladly enjoyed not living my last 10 days. ^^ -- 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.
[appengine-java] Re: Disappointment about JPA relationships :(
I agree the documentation isn't fabulous for JPA, in that a vast majority of it focuses on the JDO implementation and you end up having to work out which bits of DataNucleus documentation should be used and is relevant for GAE. However, to give the team a bit of credit the restrictions you are talking about are clearly documented at http://code.google.com/appengine/docs/java/datastore/transactions.html. Having been through the pain with trying a JPA-based implementation and reading through these message groups, it is quite clear that JDO and JPA are just a very poor fit for the underlying datastore - using the low-level API, or one of the open-source libraries such as Objectify, Twig or Slim3 is probably a safer bet. On Oct 25, 4:01 am, Shawn Brown wrote: > > I'm just here because i feel i need to rant a little. I came here expecting > > way too much. > > Been there with JDO -- the docs are not adequate. > > I don't know your exact requirements but I suspect you'll find many on > this list who found objectify to be the "simplest convenient interface > to the Google App Engine > datastore".http://code.google.com/p/objectify-appengine/ > > Shawn -- 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.
Re: [appengine-java] Re: Disappointment about JPA relationships :(
*Sir, Thanks for your guidelines. Thankyou. * On Sun, Oct 24, 2010 at 5:14 PM, Vikas Hazrati wrote: > Hi Matthieu, > > You are right, you need some conditioning and then you need to work > around the limitations of working with relationships around JPA. Then > finally you tend to realize more and more that may be you are better > off with unowned relationships > > Here are the issues that we faced and tried to resolve > http://wp.me/pNh6u-6b > > Regards | Vikas > www.inphina.com > > On Oct 23, 9:01 pm, Matthieu Bertin wrote: > > Hello, > > > > I'm just here because i feel i need to rant a little. I came here > > expecting way too much. I'm of course blaming me for being way too > > optimistic but i also believe ranting against google is somehow > > justifiable, and i'll explain why. > > > > I've started porting an application on Google App engine and i'm now > > sick of discovering exceptions like : > > > > - Detected attempt to establish PictureThread(28) as the parent of > > Picture(27) but the entity identified by Picture(27) has already been > > persisted without a parent. A parent cannot be established or changed > > once an object has been persisted > > - cannot operate on two differents types of entities in the same > > request/transaction'. Your documentation has headed me in the wrong > > direction; all you mention is 'unowned relationships' and 'many-to-many > > relationships' are not supported. > > Please fix that. Give us the real limitations on the documentation! > > There is no mention of "one to one" limitations or 'handling multiple > > entities in same transaction' limitations anywhere. > > > > It would totally be understandable not to mention theses limitations > > when JDBC APIs were created, but nowadays, when you mention 'JPA', this > > kind of limitations HAVE to be mentionned. > > -- > 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. > > -- 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.
[appengine-java] Re: Disappointment about JPA relationships :(
Hi Matthieu, You are right, you need some conditioning and then you need to work around the limitations of working with relationships around JPA. Then finally you tend to realize more and more that may be you are better off with unowned relationships Here are the issues that we faced and tried to resolve http://wp.me/pNh6u-6b Regards | Vikas www.inphina.com On Oct 23, 9:01 pm, Matthieu Bertin wrote: > Hello, > > I'm just here because i feel i need to rant a little. I came here > expecting way too much. I'm of course blaming me for being way too > optimistic but i also believe ranting against google is somehow > justifiable, and i'll explain why. > > I've started porting an application on Google App engine and i'm now > sick of discovering exceptions like : > > - Detected attempt to establish PictureThread(28) as the parent of > Picture(27) but the entity identified by Picture(27) has already been > persisted without a parent. A parent cannot be established or changed > once an object has been persisted > - cannot operate on two differents types of entities in the same > request/transaction'. Your documentation has headed me in the wrong > direction; all you mention is 'unowned relationships' and 'many-to-many > relationships' are not supported. > Please fix that. Give us the real limitations on the documentation! > There is no mention of "one to one" limitations or 'handling multiple > entities in same transaction' limitations anywhere. > > It would totally be understandable not to mention theses limitations > when JDBC APIs were created, but nowadays, when you mention 'JPA', this > kind of limitations HAVE to be mentionned. -- 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.
