How do I make child and parent entities in GAE Python?

Question

I have the following database models in my application:

class Account(ndb.Model):
    username = ndb.StringProperty()
    userid = ndb.IntegerProperty()
    email = ndb.StringProperty()

class Post(nbd.Model):
    text = nbd.StringProperty()

How can I tell the program that "many posts belong to one account" ?

Thanks!

Answer 1

There are a couple ways I think. One easy way is to just add another field on the Post model which ties it to the Account. eg assuming that all accounts have a unique userid :

def Post(ndb.Model):
    text = ndb.StringProperty()
    userid = ndb.IntegerProperty()

Now, if you have an account, you can get it's "children" by querying where the userid is the same as that of the account.

A second way is to structure your data for "strong consistency" by using "ancestor paths" . Then you can get the posts by doing an "ancestor query" .