Can you post the code for your query? Child objects are lazily loaded, so if you close the Persistence Manager before retrieving them it will return an empty List.
On Wed, Jan 20, 2010 at 4:34 PM, Dave <[email protected]> wrote: > I had gotten my application to save data, but my queries are returning > nothing. I see my data in both the parent and the child. I am getting > a "java.lang.IndexOutOfBoundsException: Index: 0, Size: 0" error when > I try to iterate through the child data. One of the strangest thing is > that my primary Key value in the child table has a value of 1 for all > the entities. This Key value should have been auto-generated by > BigTable. Additionally, when I try to edit child I see something of > the sort "Decoded entity key: ParentDB: id=6 > ChildDB: id=1" at the > top of the page. Is this data at the top of the page telling me that I > can retrieve both parent and child? > > > > On Jan 20, 4:50 pm, "Ikai L (Google)" <[email protected]> wrote: > > There should be plenty of examples around, but here is one from Max > Ross's > > blog: > > > > http://gae-java-persistence.blogspot.com/2009/10/creating-bidrectiona... > > > > We're looking at expanding the capabilities of the App Engine Cookbook to > > support examples like this contributed by the community. > > > > > > > > On Tue, Jan 19, 2010 at 4:48 PM, Dave <[email protected]> wrote: > > > I have been working assiduously on a GWT project. I have implemented > > > the stockwatcher app without problems. It's new to me to be working > > > with JDO/JPA. I'm more in tuned to using relational DB. There are no > > > concrete application example that deals with one to many DB. I have > > > read some of the documentation to create and use a one to many DB. I > > > have been able to save the one to many data, but I'm unable to > > > retrieve the data. I don't fully understand it all. Google should > > > recognize that many people learn by doing. There needs to be a sample > > > application with one to many relationships (and many to many). > > > > > If Google's only tutorial on GWT was like what is shown here > > >http://code.google.com/appengine/docs/java/datastore/relationships.html > . > > > Then less people would have used it. I know I'll learn how to > > > implement one to many properly by 'googling' the Internet. However, it > > > could have been less painful! Please post a sample application > > > > > -- > > > 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 > > > [email protected]. > > > To unsubscribe from this group, send email to > > > [email protected]<google-appengine-java%[email protected]> > <google-appengine-java%[email protected]<google-appengine-java%[email protected]> > > > > > . > > > For more options, visit this group at > > >http://groups.google.com/group/google-appengine-java?hl=en. > > > > -- > > Ikai Lan > > Developer Programs Engineer, Google App Engine > > -- > 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 > [email protected]. > To unsubscribe from this group, send email to > [email protected]<google-appengine-java%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/google-appengine-java?hl=en. > > > > -- Ikai Lan Developer Programs Engineer, Google App Engine -- 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 [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-appengine-java?hl=en.
