Thanks Andrey, that works perfectly. I wasn't understanding the example in the docs about this:
http://code.google.com/appengine/docs/java/datastore/transactions.html section titled "Creating Entities With Entity Groups". Your example makes it clear, Thanks On Apr 27, 6:04 am, ailinykh <[email protected]> wrote: > define Cow as > > class Cow { > @PrimaryKey > @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) > private Key id; > > @Persistent > @Extension(vendorName="datanucleus", key="gae.parent-pk", > value="true") > private Key farmKey; > > } > > If you set farmKey to farm id then both farm and cow will be in the > same entity group. > > this code should work: > > tx.begin() > > Farm f = getFarm(); > Cow c = new Cow(); > c.setFarmKey(f.getId()); > f.incCowCounter(); > pm.makePersistent(c); //if you need to know new cow id. > > tx.commit(); > > Andrey > > -- > 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 > 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 [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.
