Two things.... 1. More importantly, what is the detail of your javax.jdo.JDOUserException, and what is your code that is associated with this exception?
2. I personally use bi-directional relationships between parent and children. So in your case, you could add to your Tweeter class: @Persistent(mappedBy="tweeter") @Element(dependent="true") @Order(extensions = @Extension(vendorName="datanucleus", key="list- ordering", value="key ASC")) private ArrayList<Truck> liTrucks = new ArrayList<Truck>(); but you might want to omit the "@Element" line. On Sep 26, 11:07 pm, culov <cul...@gmail.com> wrote: > I'm looking to tighten up some of my server-side code, but I'm having > trouble properly establishing the relationship between entities. > Before, I was using unencoded Strings as keys, but after reading the > documentation here, I've changed them to encoded app-generated > Strings. > > I have two Entities, Trucks and Tweeters. What I'd like is an > accessible Tweeter inside every Truck. Every truck has to have a > Tweeter associated with it (there may be many Trucks with the same > Tweeter), but a Tweeter may have no Trucks. Thus, the Tweeter should > be the parent, and the Truck the child. I'm having lots of trouble > persisting the classes in the datastore and I'm hoping someone can > look over how I created the classes and detect my errors. Currently im > getting a javax.jdo.JDOUserException. When I try to persist a Truck > object. Here's the relevant portion of my child class, Truck: > > @PrimaryKey > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) > @Extension(vendorName="datanucleus", key="gae.encoded-pk", > value="true") > private String key; > .... > @Persistent(defaultFetchGroup = "true") > private Tweeter tweeter; > and the parent, Tweeter: > > @PrimaryKey > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) > @Extension(vendorName="datanucleus", key="gae.encoded-pk", > value="true") > private String key; > I never set any of the keys anywhere, and based on the logs, the keys > are being set as they should be. I think there must be a critical > misunderstanding of the relationship on my part thats leading me to > see an error regardless of what I try. I know I can use > com.google.appengine.api.datastore.Key, but my classes are also used > client-side by GWT, so I can't import the Key class from the GAE > library. > > Thanks so much for the help! -- 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.
