Google App Engine ndb query

Question

I have created an Entity, called "Event" in the Google Cloud Datastore for my project. The entity has an ID generated by AppEngine followed by two properties

• Location
• Date

I am trying to query this entity by its ID (5629499534213120), so , here is my code.

 key = 5629499534213120
 e = Event.get_by_id(key)
 logging.info("Event Location = %s" % e.Location)

The value of e is NoneType.

code

 __author__ = 'vinayjoseph'
from google.appengine.ext import ndb
import logging
class Event(ndb.Model):
 """Models an individual event at xxx xxxx """
 Date = ndb.DateTimeProperty()
 Location = ndb.StringProperty()
def get_meeting_date():
 """gets the next meeting date from the No SQL Schemaless Google Datastore
 """
 key = 5629499534213120
 e = Event.get_by_id(key)
 logging.info("Event Location = %s" % e.Location)

e is NoneType

In the datastore I see the following at https://console.developers.google.com/project/apps~xxxxx/datastore/editentity?key=xxxxx%2FEvent%20id:5629499534213120

screen shot of the entity in the datastore

I suspect the problem might be with my key.

When I try to query the datastore in development using dev_appserver.py it works. I am using a different key for dev.

def get_meeting_date():
 """gets the next meeting date from the No SQL Schemaless Google Datastore
 """
 #dev
 key = 6401356696911872
 #prd
 #key = 5629499534213120
 e = Event.get_by_id(key)
 logging.info("Event Location = %s" % e.Location)

enter image description here

• Ryan: Try adding quotes around the ID event_key = ndb.Key("Event", "5629499534213120")
• GAEfan: ID should be int int, so that should be fine. Does this entity have a parent entity?
• Vinay Joseph: Tried both and it did not work And no it does not have a parent entity

Answer 1

OK so I finally figured it out.

I had to make a few changes to the entity itself, just to get the filtering right. So the new properties are as seen below. Entity Properties

The code in python is as follows:

__author__ = 'vinayjoseph'
from google.appengine.ext import ndb
import logging
from datetime import datetime
class Event(ndb.Model):
 """Models an individual event at xxx xxx """
 Date = ndb.DateTimeProperty()
 Location = ndb.StringProperty()
 Address = ndb.StringProperty()
 Name = ndb.StringProperty()
def get_meeting_date():
 """gets the next meeting date from the No SQL Schemaless Google Datastore
 """
 qry = Event.query(Event.Name == 'Next Meeting Location')
 for event in qry.fetch(1):
 logging.info("Meeting is on %s at %s" % (str(event.Date), event.Address))

And it works like a charm. Check out the log entry in app-engine

enter image description here

Answer 2

In the query method, you're using ancestor. If your entities have a parent, then you have to include it in the get_by_id call.

• Vinay Joseph: Yes, however I am not using this method anymore. The event var is of type NoneType in the get_meeting_date() method.