== No More JOINs ==
SELECT * FROM actor
  JOIN actor_preferences ON actor_preferences.actor = actor.id
  WHERE actor.name = 'zed'

becomes

query = Actor.gql('WHERE name = :1', 'zed') 
actor_refs = Actor.get_by_key_name([row.id for row in query])


Note: 

get([100 keys]) 

is also quite a bit faster than 

(get(key) for key in [100 keys])


== No More Slowness ==

nice article on indexes in app engine: http://code.google.com/appengine/articles/index_building.html


== DictProperty ==
from http://code.google.com/p/jaikuengine/source/browse/trunk/common/properties.py


from google.appengine.ext import db
from google.appengine.api.datastore_types import Blob

class DictProperty(db.Property):
  def validate(self, value):
    value = super(DictProperty, self).validate(value)
    if not isinstance(value, dict):
      raise Exception("NOT A DICT %s" % value)
    return value

  def default_value(self):
    return {}

  def datastore_type(self):
    return Blob

  def get_value_for_datastore(self, model_instance):
    value = super(DictProperty, self).get_value_for_datastore(model_instance)
    return Blob(pickle.dumps(value, protocol=-1))

  def make_value_from_datastore(self, model_instance):
    value = super(DictProperty, self).make_value_from_datastore(model_instance)
    return pickle.loads(str(value))


== Efficient Paging Using __key__ ==

http://groups.google.com/group/google-appengine/browse_thread/thread/ee5afbde20e13cde

== Entity Groups ==

If you're keen, learn how to use them here:
http://code.google.com/appengine/docs/python/datastore/keysandentitygroups.html


== Zip it up ==
from http://code.google.com/p/jaikuengine/source/browse/trunk/build.py

import zipfile
ZIP_SKIP_RE = re.compile('\.svn|\.pyc|\.[pm]o')
IGNORED_CONTRIB = ('admin', 'gis', 'comments', 'localflavor', 'databrowse')

def zip_vendor_lib(lib):
  f = zipfile.ZipFile('%s.zip' % lib, 'w')

  for dirpath, dirnames, filenames in os.walk('vendor/%s' % lib):
    if dirpath == os.path.join('vendor', lib, 'contrib'):
      _strip_contrib(dirnames)

    for filename in filenames:
      name = os.path.join(dirpath, filename)
      if ZIP_SKIP_RE.search(name):
        logging.debug('Skipped (skip_re): %s', name)
        continue
      if not os.path.isfile(name):
        logging.debug('Skipped (isfile): %s', name)
        continue
      logging.debug('Adding %s...', name)
      f.write(name, name[len('vendor/'):], zipfile.ZIP_DEFLATED)

  f.close()



== Conditional Properties (for now) ==
if settings.APP_ENGINE:
    from appengine_django.models import db, BaseModel
    Model = BaseModel
else:
    from django.db import models
    Model = models.Model


class Blog(Model):
    if settings.APP_ENGINE:
        title = db.StringProperty(required=True)
        author = db.ReferenceProperty(User)
    else:
        title = models.CharField(_("title"), max_length=100)
        author = models.ForeignKey(User, related_name=_("author"))