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Questions tagged [app-engine-ndb]

NDB is a better datastore API for the Google App Engine Python runtime. It provides an improved interface over ext.db, and includes support for parallel processing with coroutines.

NDB is a better datastore API for the Google App Engine Python runtime, and currently a standard component of the App Engine Python SDK and the Python runtime.

The NDB API provides persistent storage in a schemaless object datastore. It supports automatic caching, sophisticated queries, and atomic transactions. NDB is well-suited to storing structured data records.

Documentation.

Conversion guide from old db.

Original [deprecated] project.

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AppEngine NDB property validations

I wonder what the best approach is for validating NDB entity properties likes: a date must be in the future a grade (integer property) must be between 1 and 10 a reference to another entity must have certain property values (e.g.…
Marcel Overdijk
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How can I fetch the lastest entry of a model new put into NDB?

How can I get the latest entry of a model new putted into NDB? 1: If I use a same parent key ? How to ? I see the document write Entities whose keys have the same root form an entity group or group. If entities are in different groups, then…
zuroc
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blob_send save_as=True fails after converting from db to ndb

I converted nicks blog example to ndb now this line fails: self.send_blob(file_info.blob, save_as=True) with this error: ValueError: Expected BlobInfo value for blob_key_or_info. Rest of the class: class…
user784435
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Comparing a key to a KeyProperty in ndb

I'm trying to make a query comparing a key but i don't get any results. I have a Tutorial and a Chapter Model. The chapter Model contais a keyProperty of kind Tutorial. ( tutKey = ndb.KeyProperty(kind='Tutorial')) tutID =…
mFontoura
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Data Modeling - modeling an Append-only list in NDB

I'm trying to make a general purpose data structure. Essentially, it will be an append-only list of updates that clients can subscribe to. Clients can also send updates. I'm curious for suggestions on how to implement this. I could have a ndb.Model,…
Murph
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NDB Parallel Tasklets

Please take a look at this parallel tasklet code snippet #1. @ndb.tasklet def get_data_parallel(e): usr, det = yield (e.user.get_async(), MyKind.query(ancestor = e.key).fetch_async()) raise…
Moisés Belchín
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Storing Data - Big list into entity properties

I run a crawler back-end in my application that everyday mines some websites for data. For every website I crawl I create an entity, stores a big list of String id's. Approximation is around 2.000 per entity. Around 1000 entities per day. The…
Jimmy Kane
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AppEngine NDB PolyModel getting properties

I am having a problem with appengine that I can't seem to figure out: from google.appengine.ext import ndb from google.appengine.ext.ndb import polymodel class Item(polymodel.PolyModel): name = ndb.StringProperty() type =…
Jon
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Understanding AppEngine _ah/stats result

I have this result in App Stats for AppEngine, and I can't work it out, it looks like each part performs ok, but there is a huge gap. Any Ideas? Context: It's a registration system, it checks if the username/email already exists, send an email to…
Chris
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python Channel API expiry and usage in google app engine

I want to use the channel api to push updates to open pages, What I have done so far is to store the page client ids in ndb - I have included a code summary My question is: How do I manage closed pages and expired tokens? and is this the best way to…
user784435
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Google Appengine / Django / NDB setup throws mysqldb error on server start

I'm running Django 1.3 in a virtualenv with python 2.7 on OSX Mountain Lion. When I run dev_appserver.py I get this thrown at me. (Ignore the warning about the images API. Question: Why am I getting a mysqldb warning when I'm using ndb? Question:…
mehulkar
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Dereference Models from many to many relationship

In my schema, as described in the below test data generation example, I want to know a good way to: Dereference all instances of Favourites that have reference keys to instances of Pictures that have been deleted. Just delete any Favourite that…
Jimmy Kane
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performance implications of transactions on large entity groups (python, NDB, Master/Slave)

I have several tens of thousands of related small entities (NDB atop of Master-Slave, will have to move to HRD one day..), which I'd like to put in the same entity group to enable transactions. Small subsets of those entities will be updated by…
Srg
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NDB query periodically not finding entity

I have an account key that I check when processing items. This key prevents me from spending time working on items that are no longer valid. On an inner loop in processing, I validate that I can still find the key that I am working on. Entity…
TheJacobTaylor
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app engine datastore transaction exception

In app engine transactions documentation I have found the following note: Note: If your app receives an exception when submitting a transaction, it does not always mean that the transaction failed. You can receive Timeout,…
Slawek Rewaj
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