Question

I am fetching records from gae model using cursor() and with_cursor() logic as used in paging. but i am not sure how to check that there is no any other record in db that is pointed by cursor. i am fetching these records in chunks within some iterations.when i got my required results in the first iteration then in next iteration I want to check there is no any record in model but I not get any empty/None value of cursor at this stage.please let me know how to perform this check with cursors in google app engine with python.

Answer 1

If your model is extending ndb, you should use fetch_page(). If it’s not extending ndb, you may want to consider changing. It’s not completely backwards compatible but the data does not have to be migrated.

from google.appengine.ext.ndb import model

class User(model.Model):
   name = model.StringProperty()

users, cursor, more = User.query(User.name == "Jon").fetch_page(25)

if more: 
    # Do next page logic
    next_users = User.query(User.name == "Jon").fetch_page(25, start_cursor=cursor)