Yes, you will need to create an entity parent. Note that the more entity groups you can create, the better performance you will have. See this document: http://code.google.com/appengine/docs/python/datastore/keysandentitygroups.html
>From that link: A good rule of thumb for entity groups is that they should be about the size of a single user's worth of data or smaller. On Wed, Nov 11, 2009 at 1:31 PM, Simo Salminen <[email protected]> wrote: > > I have database entities that I want to change in transaction. For > this I have to create an entity group. However, the entities don't > have any natural parent entity, so I have created a dummy parent > entity. Is there another good way to do this? > > Currently I am using the system below. First, I have following data > model. > > class Event(db.Model): > date = db.DateTimeProperty(required=True) > name = db.StringProperty(required=True) > > I have created a "dummy" parent: > class Parent(db.Model): > pass > > Creating parent and defining the parent for the entity (this code is > inside the transaction): > try: > k = db.get("parent_key") > except db.BadKeyError: > k = models.Parent(key_name="parent_key") > k.put() > > ancestor_key = k.key() > q = db.GqlQuery('SELECT * WHERE ANCESTOR IS :1', ancestor_key) > # (using the query results here, code clipped) > e = models.Event(date=date, name=name, parent=k) > e.put() > > > Can I avoid creating this dummy "Parent" model, and satisfy the > "entity group/transaction" requirement in more elegant way? > > --~--~---------~--~----~------------~-------~--~----~ > 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]<google-appengine%[email protected]> > For more options, visit this group at > http://groups.google.com/group/google-appengine?hl=en > -~----------~----~----~----~------~----~------~--~--- > > -- Ikai Lan Developer Programs Engineer, Google App Engine -- 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=.
