Unique constraints for Google Appengine NDB

NDBUnq emulates unique constraints on Google Appengine Datastore using NDB hooks.

Example

There is full working example for Flask: https://github.com/vmihailenco/ndbunq-example/:

import ndbunq
from google.appengine.ext import ndb


class User(ndbunq.Model):
    username = ndb.StringProperty(required=True)

    class Meta:
        # username is guaranteed to be unique
        unique = (('username',),)