Question

Changing question. I Want to apply ManyToMany relationship between db.Model and NDB.
example

NDB model

class my_NDB(search.SearchableModel):
   .......
   .......

db model

class Test(search.SearchableModel):
  email = db.StringProperty()
  created_by = db.IntegerProperty()

Can I apply ManyToMany relationship between these models?

EDIT:

Here is my User Model

  class User(model.Expando):
    """Stores user authentication credentials or authorization ids."""

    #: The model used to ensure uniqueness.
    unique_model = Unique
    #: The model used to store tokens.
    token_model = UserToken

    created = model.DateTimeProperty(auto_now_add=True)
    updated = model.DateTimeProperty(auto_now=True)
    # ID for third party authentication, e.g. 'google:username'. UNIQUE.
    auth_ids = model.StringProperty(repeated=True)
    # Hashed password. Not required because third party authentication
    # doesn't use password.
    email = model.StringProperty(required=True)
    is_active = model.BooleanProperty(required=True)
    password = model.StringProperty()

And Here is my Test db model

class Test(search.SearchableModel):
  email = db.StringProperty()
  created_by = db.IntegerProperty()

Now I want to apply manyToMany on Test. Is it possible?

Django style ManyToMany

created_by = models.ManyToManyField(User)

Answer 1

I see. I had to look up the Django ManyToManyField docs. IIUC you want a Test to be created by multiple users, and of course each user can create multiple tests. Have I got that right?

The way to do this would be to have a db.ListProperty(db.Key) in the Test class, so that the Test class has a list of keys — where the keys point to User entities.

Now your User model is an NDB class, which complicates matters a bit. However the ndb Key class has an API for converting to and from db Keys:

• If you have an ndb Key k, k.to_old_key() returns the corresponding db.Key.

• If you have a db Key k, ndb.Key.from_old_key(k) returns the ndb.Key for it (it’s a class method).

Hope this helps. Good luck!

PS. Please update your code to use from google.appengine.ext import ndb so you can write ndb.Expando, ndb.StringProperty, etc.