quote from GAE document - Model

appengine_model.py

# ref: http://code.google.com/intl/ja/appengine/docs/python/datastore/entitiesandmodels.html

# -----
# Model
# ref: http://code.google.com/intl/ja/appengine/docs/python/datastore/modelclass.html
# -----

from google.appengine.ext import db

class Pet(db.Model):
    name = db.StringProperty(required=True)
    type = db.StringProperty(
               required=True, choices=set(["cat", "dog", "bird"])
           )
    birthdate = db.DateProperty()
    weight_in_pounds = db.IntegerProperty()
    spayed_or_neutered = db.BooleanProperty()
    owner = db.UserProperty(required=True)


from google.appengine.api import users

pet = Pet(name="Fluffy",
          type="cat",
          owner=users.get_current_user())
pet.weight_in_pounds = 24

# -------------
# Expando Model
# ref: http://code.google.com/intl/ja/appengine/docs/python/datastore/expandoclass.html
# -------------

class Person(db.Expando):
    first_name = db.StringProperty()
    last_name = db.StringProperty()
    hobbies = db.StringListProperty()

p = Person(first_name="Albert", last_name="Johnson")
p.hobbies = ["chess", "travel"]

p.chess_elo_rating = 1350

p.travel_countries_visited = ["Spain", "Italy", "USA", "Brazil"]
p.travel_trip_count = 13

p1 = Person()
p1.favorite = 42
p1.put()

p2 = Person()
p2.favorite = "blue"
p2.put()

p3 = Person()
p3.put()

people = db.GqlQuery("SELECT * FROM Person WHERE favorite < :1", 50)
# people has p1, but not p2 or p3

people = db.GqlQuery("SELECT * FROM Person WHERE favorite > :1", 50)
# people has no results

# ------------------
# Poliymorphic Model
# ref: http://code.google.com/intl/ja/appengine/docs/python/datastore/polymodelclass.html
# ------------------

from google.appengine.ext import db
from google.appengine.ext.db import polymodel

class Contact(polymodel.PolyModel):
    phone_number = db.PhoneNumberProperty()
    address = db.PostalAddressProperty()

class Person(Contact):
    first_name = db.StringProperty()
    last_name = db.StringProperty()
    mobile_number = db.PhoneNumberProperty()

class Company(Contact):
    name = db.StringProperty()
    fax_number = db.PhoneNumberProperty()

p = Person(phone_number='1-206-555-9234',
           address='123 First Ave., Seattle, WA, 98101',
           first_name='Alfred',
           last_name='Smith',
           mobile_number='1-206-555-0117')
p.put()

c = Company(phone_number='1-503-555-9123',
            address='P.O. Box 98765, Salem, OR, 97301',
            name='Data Solutions, LLC',
            fax_number='1-503-555-6622')
c.put()

for contact in Contact.all():
    print 'Phone: %s\nAddress: %s\n\n'
          % (contact.phone, contact.address)

for person in Person.all()
    print 'Phone: %s\nAddress: %s\n\n'
          % (contact.phone, contact.address)

for company in Company.all()
    print 'Phone: %s\nAddress: %s\n\n'
          % (contact.phone, contact.address)