CODEWITHSUNDEEP
pythongoogle-app-enginegoogle-cloud-datastore
Lee Gellie
Lee Gellie

Reputation: 99

Python ndb Datastore put list to Datastore

I am trying to populate a Datastore with my older course notes so that in future I can add notes like a comments board or guestbook.

I can't seem to get the previous notes in the Datastore and have been trolling over GAE documentation and searching the web to no avail.

Here is my code:

import time
import cgi
import os
import jinja2
import webapp2
from google.appengine.ext import ndb

jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir), autoescape = True)

dataEntery = [[1, 4, 'Networks','''
            <p>A network is a group of entities that can communicate, even </p>'''],
[2, 4, 'Measuring Networks','''
            <p>The two main ways of measuring a network are;</p>
      '''], etc]

class CourseData(ndb.Model):
    id_index = ndb.IntegerProperty()
    stage_number = ndb.IntegerProperty()
    note_title = ndb.StringProperty(indexed=False)
    note_content = ndb.StringProperty(indexed=False)

for a in dataEntery:
    newEntry = CourseData(id_index=a[0], stage_number=a[1], note_title=a[2], note_content=a[3])
    newEntry.put()
    time.sleep(.2)

class MainHandler(webapp2.RequestHandler):
    def get(self):
        self.response.out.write('''
            <!DOCTYPE HTML>
                <html>
                    <head>
                        <title>Lee's Notes</title>
                        <link href="../styles.css" rel="stylesheet" type="text/css">
                    </head>
                    <body>
                    <h1 class="opener">Lee's Notes on Intro to Programming</h1>
                    ''')
        query = CourseData.query(stage_number == 4).fetch()
        self.response.out.write('<article id="note%s"><h2>%s</h2>' % cgi.escape(query.note_title), cgi.escape(query.note_title))
        self.response.out.write('%s</article>' % cgi.escape(query.note_content))

app = webapp2.WSGIApplication([
        ('/', MainHandler)], debug=True)

Upvotes: 2

Views: 229

Answers (1)

Jesse
Jesse

Reputation: 8393

First thing to note is that the appengine datastore is eventually consistent. Read this article: https://cloud.google.com/appengine/docs/python/datastore/structuring_for_strong_consistency?hl=en

For you're case you don't really need a query. Make a good index and then retrieval is a lot easier with a key.get(). Note, this is assuming you don't want to use id_index...

for a in dataEntery:
    entityKey = ndb.Key(CourseData._get_kind(), stage_number=a[1])
    newEntry = CourseData(key=entityKey, id_index=a[0], stage_number=a[1], note_title=a[2], note_content=a[3])
    newEntry.put()

Retrieval then becomes:

entity_key = CourseData.build_key(4)

Upvotes: 1

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