app-engine-ndb

Let's say there is ndb.Model that looks like this: class Foo(ndb.Model): bar = ndb.StringProperty() My question is, if my only input is the Foo.query() how can I get the model as an object that this query belongs to? def query_to_model(query): # some magic return model The Foo.query().kind return the model's name as a string, but I didn't manage to find a way to get it as an object. The following works using eval , but only when the model is defined in the same file: def query_to_model(query): return eval(query.kind) I want something more general than that. Greg After you have imported code

I am trying to develop an web app on google app engine using webapp2. One of the thing I need to do is to retrieve a random from ndb and display it. Is it any effective method that allows me to do so? I assume you mean a random record when you say "random from ndb". If you are using automatic id's you could use the following approach. (how sparse you id's will affect how successful this will be). use random.randrange(start, stop) with start being 0, stop being (2^52)-1 , given the new id allocation policy. do a keys only query for keys greater than key created from random id. if no results try

I have this entity model: class ApartCILabel(ndb.Model): project_id = ndb.IntegerProperty(indexed=True) changeset_ids = ndb.IntegerProperty(repeated=True, indexed=True) # ApartCIChangeset IDs # other properties I recently added a new type of query for these entities: keys = ApartCILabel.query(ApartCILabel.project_id == self.db_data.project_id, ApartCILabel.changeset_ids == self.key_id).fetch(keys_only=True) if keys: label = Label(db_key=keys[0], handler=self.handler) logging.debug('label found: %s' % label.name) else: logging.error('label for %s not found' % self.lid) I knew I needed a

I am trying to write a test for my GAE programme which uses the datastore. Following Google's Documentation , I see that I should be adding the path to my SDK into my PYTHONPATH. I did this using: import sys sys.path.remove('/usr/local/lib/python2.7/dist-packages') # Has a 'google' module, which I want to be sure isn't interfering. sys.path.insert(1,'/home/olly/google-cloud-sdk/platform/google_appengine') sys.path.insert(1, '/home/olly/google-cloud-sdk/platform/google_appengine/lib/yaml/lib') Then when the file is run: Traceback (most recent call last): File "myapp_tests.py", line 20, in

Is there an equivalent for modelname_set (a back-referenced property) in Google App Engine's NDB ? In the old DB a Model entity had described the back-reference property as : The name of the back-reference property defaults to modelname_set (with the name of the model class in lowercase letters, and "_set" added to the end), and can be adjusted using the collection_name argument to the ReferenceProperty constructor. I noticed this property does not seem to exist with NDB db.Model instances. Does NDB have an equivalent to the back-reference property? There is no direct back-reference properties

I'm having a problem and I don't find any information about. I define a field in my model like this. class Dates(ndb.model): ... date = ndb.DateTimeProperty(required = True) # I want to store date and time ... Later I try a query (now I want all the dates for a day, I don'tn mind the time): kl = Dates.query(ndb.AND(Dates.date.year == year, Dates.date.month == month, Dates.date.day == day), ancestor = customer.key).fetch(keys_only = True) dates = ndb.get_multi(kl) But I get this error log: AttributeError: 'DateTimeProperty' object has no attribute 'year' I don't know why. I've tried Dates.date(

An NDB model contains two properties: email and password . How to avoid adding to the database two records with the same email ? NDB doesn't have UNIQUE option for a property, like relational databases do. Checking that new email is not in the database before adding—won't satisfy me, because two parallel processes can both simultaneously do the checking and each add the same email . I'm not sure that transactions can help here, I am under this impression after reading some of the manuals. Maybe the synchronous transactions ? Does it mean one at a time? Create the key of the entity by email,

I'm having trouble with Google's App engine indexes. When running my app via the GoogleAppEngineLauncher, the app is working fine. When deploying the app, I get the following error: NeedIndexError: no matching index found. The suggested index for this query is: - kind: Bar ancestor: yes properties: - name: rating direction: desc The error is generated after this line of code: bars = bar_query.fetch(10) Before the above line of code, it reads: bar_query = Bar.query(ancestor=guestbook_key(guestbook_name)).order(-Bar.rating) My index.yaml file contains the exact "suggested" index below #