You might want to have a look at this: http://code.google.com/appengine/docs/java/javadoc/com/google/appengine/api/datastore/DatastoreService.html#allocateIds(com.google.appengine.api.datastore.Key, java.lang.String, long)
You can specify a parent and allocate IDs. The only caveat is that these may not be guaranteed to be sequential: just unique. On Wed, Aug 25, 2010 at 4:24 AM, markus <[email protected]> wrote: > Hello all! > > I have a datastore class "User", which has a property key of type Key > as its primary key. > > Now, I want to store objects of type "Result" in the datastore, as > children of the User in an unowned relationship. Each result has a > property key of type Key as its primary key as well. > > For creating the key of the child, I currently use the > Key.getChild(String kind, String name) method on the parent key (see > > http://code.google.com/appengine/docs/java/javadoc/com/google/appengine/api/datastore/Key.html#getChild%28java.lang.String,%20java.lang.String%29 > ), > specifically like this: > > Key key = user.getKey().getChild(Result.class.getSimpleName(), > UUID.randomUUID().toString()); > > The problem is, I'm quite sure that the UUID class doesn't guarantee > uniqueness in a distributed setting like GAE. Is there a way to > generate a unique name here, or preferably let the datastore handle > uniqueness? Like a Key.getChild(String kind) method. > > Regards, > Markus > > -- > 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 Blog: http://googleappengine.blogspot.com Twitter: http://twitter.com/app_engine Reddit: http://www.reddit.com/r/appengine -- 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.
