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import datetime
from django.db import models
from django.db.models.fields.related import \
ReverseSingleRelatedObjectDescriptor
from django.utils.encoding import python_2_unicode_compatible
from django.utils.translation import get_language
@python_2_unicode_compatible
class Country(models.Model):
# Table Column Fields
name = models.CharField(max_length=50)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Person(models.Model):
# Table Column Fields
name = models.CharField(max_length=128)
person_country_id = models.IntegerField()
# Relation Fields
person_country = models.ForeignObject(
Country, from_fields=['person_country_id'], to_fields=['id'])
friends = models.ManyToManyField('self', through='Friendship', symmetrical=False)
class Meta:
ordering = ('name',)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Group(models.Model):
# Table Column Fields
name = models.CharField(max_length=128)
group_country = models.ForeignKey(Country)
members = models.ManyToManyField(Person, related_name='groups', through='Membership')
class Meta:
ordering = ('name',)
def __str__(self):
return self.name
@python_2_unicode_compatible
class Membership(models.Model):
# Table Column Fields
membership_country = models.ForeignKey(Country)
date_joined = models.DateTimeField(default=datetime.datetime.now)
invite_reason = models.CharField(max_length=64, null=True)
person_id = models.IntegerField()
group_id = models.IntegerField()
# Relation Fields
person = models.ForeignObject(
Person,
from_fields=['membership_country', 'person_id'],
to_fields=['person_country_id', 'id'])
group = models.ForeignObject(
Group,
from_fields=['membership_country', 'group_id'],
to_fields=['group_country', 'id'])
class Meta:
ordering = ('date_joined', 'invite_reason')
def __str__(self):
return "%s is a member of %s" % (self.person.name, self.group.name)
class Friendship(models.Model):
# Table Column Fields
from_friend_country = models.ForeignKey(Country, related_name="from_friend_country")
from_friend_id = models.IntegerField()
to_friend_country_id = models.IntegerField()
to_friend_id = models.IntegerField()
# Relation Fields
from_friend = models.ForeignObject(
Person,
from_fields=['from_friend_country', 'from_friend_id'],
to_fields=['person_country_id', 'id'],
related_name='from_friend')
to_friend_country = models.ForeignObject(
Country,
from_fields=['to_friend_country_id'],
to_fields=['id'],
related_name='to_friend_country')
to_friend = models.ForeignObject(
Person,
from_fields=['to_friend_country_id', 'to_friend_id'],
to_fields=['person_country_id', 'id'],
related_name='to_friend')
class ArticleTranslationDescriptor(ReverseSingleRelatedObjectDescriptor):
"""
The set of articletranslation should not set any local fields.
"""
def __set__(self, instance, value):
if instance is None:
raise AttributeError("%s must be accessed via instance" % self.field.name)
setattr(instance, self.cache_name, value)
if value is not None and not self.field.rel.multiple:
setattr(value, self.field.related.get_cache_name(), instance)
class ColConstraint(object):
# Anything with as_sql() method works in get_extra_restriction().
def __init__(self, alias, col, value):
self.alias, self.col, self.value = alias, col, value
def as_sql(self, compiler, connection):
qn = compiler.quote_name_unless_alias
return '%s.%s = %%s' % (qn(self.alias), qn(self.col)), [self.value]
class ActiveTranslationField(models.ForeignObject):
"""
This field will allow querying and fetching the currently active translation
for Article from ArticleTranslation.
"""
requires_unique_target = False
def get_extra_restriction(self, where_class, alias, related_alias):
return ColConstraint(alias, 'lang', get_language())
def get_extra_descriptor_filter(self):
return {'lang': get_language()}
def contribute_to_class(self, cls, name):
super(ActiveTranslationField, self).contribute_to_class(cls, name)
setattr(cls, self.name, ArticleTranslationDescriptor(self))
@python_2_unicode_compatible
class Article(models.Model):
active_translation = ActiveTranslationField(
'ArticleTranslation',
from_fields=['id'],
to_fields=['article'],
related_name='+',
null=True)
pub_date = models.DateField()
def __str__(self):
try:
return self.active_translation.title
except ArticleTranslation.DoesNotExist:
return '[No translation found]'
class NewsArticle(Article):
pass
class ArticleTranslation(models.Model):
article = models.ForeignKey(Article)
lang = models.CharField(max_length=2)
title = models.CharField(max_length=100)
body = models.TextField()
abstract = models.CharField(max_length=400, null=True)
class Meta:
unique_together = ('article', 'lang')
ordering = ('active_translation__title',)
class ArticleTag(models.Model):
article = models.ForeignKey(Article, related_name="tags", related_query_name="tag")
name = models.CharField(max_length=255)
class ArticleIdea(models.Model):
articles = models.ManyToManyField(Article, related_name="ideas",
related_query_name="idea_things")
name = models.CharField(max_length=255)
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