How would you design an AppEngine datastore for a social site like Twitter?

Question

I\'m wondering what would be the best way to design a social application where members make activities and follow other member\'s activities using Google AppEngine.

Answer 1

I think this can now be solved with the new Projection Queries in NDB.

class Message(ndb.Model):
    sender = ndb.StringProperty()
    receivers = ndb.StringProperty(repeated=True)
    body = ndb.TextProperty()

messages = Message.query(Message.receivers == user_id).fetch(projection=[Message.body])

Now you don't have to deal with the expensive cost of deserializing the list property.