GAE (Bigtable) doesn't support this kind of functionality. We have implemented a relational database on top of GAE (Bigtable) which supports referential integrity etc. Please check it out here,
http://www.cloud2db.com On Mon, Jan 18, 2010 at 3:08 PM, Rusty Wright <[email protected]>wrote: > In your class, if you have a Collection of entities that you want to not > have duplicates you can make it a Set, and be sure that you've provided a > proper equals() and hashCode() for your entities; specifically, do not > include the primary key because it starts out null when you instantiate the > entity, and then is set after the entity is persisted. I don't know if > there is anything on the JDO or DataNucleus site that explains this but I do > remember reading about it in either a Hibernate book or on the Hibernate > site. > > > > tal wrote: > >> How do I enforce a unique constraint in GAE? >> >> > -- > 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. > > > >--
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