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.remote_field.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)