> I'm not sure I've followed you with whole Ownership model.. > Isn't that a RDBMS approach to the data and not BigTable's?
The two approaches aren't mutually exclusive. In the case of User <-> CD, a User can have thousands or more CDs and a CD could be purchased by millions. Under those circumstances, storing the ownership relationship in a list of references under either User or CD entities will really impact performance. In Rafe Kaplan's article he says: "Another more important one is that you want to avoid storing overly large lists of keys in a ListProperty." The straightforward alternative is a separate Ownership model and now there's a separate issue of constructing a transaction that handles updating your genre counter upon a successful Ownership change. It'll be interesting if someone comes up with another approach, maybe using multiple User entities (under one entity group) that all map to a single user, with each User entity holding a subset of all the CDs and genre counters. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
