Hey Carl, What about just making the subscription's key_name something like "customer.key().id_or_name()-service.key().id_or_name()". That will prevent duplicating subscriptions.
Robert On Jul 20, 2010, at 23:42, cwaldbieser <[email protected]> wrote: > I have 3 models: A customer account, a service, and a model that > represents a customer's subscription to the service. The subscription > is essentially: > > class Subscription(db.Model): > customer = db.ReferenceProperty(Customer) > service = db.ReferenceProperty(Service) > > I have a user interface that allows creating or cancelling a > customer's subscription. I want to be able to create a subscription > only if an existing subscription does not already exist. I thought > that a transaction might be the key, but I can't do a query in > transaction unless it is by key or an ancestor query. So I am not > sure what to do. > > Any thoughts? > > Thanks, > Carl > > -- > You received this message because you are subscribed to the Google Groups > "Google App Engine" 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?hl=en. > -- You received this message because you are subscribed to the Google Groups "Google App Engine" 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?hl=en.
