我建模为一个地区的基础设施如下:每个地区都有国家的多对多,和可选的状态(如果它是在美国内的区域)Django的多对多过滤
from django.contrib.auth.models import User
from django.contrib.localflavor.us.models import USStateField
from django.db import models
from django_countries import CountryField
class CountryManager(models.Manager):
def get_by_natural_key(self, country):
return self.get(country=country)
class Country(models.Model):
country = CountryField(unique=True)
objects = CountryManager()
class Meta:
ordering = ('country',)
def __unicode__(self):
return unicode(self.country.name)
def natural_key(self):
return (self.country.code,)
class StateManager(models.Manager):
def get_by_natural_key(self, state):
return self.get(state=state)
class State(models.Model):
state = USStateField(unique=True)
objects = StateManager()
class Meta:
ordering = ('state',)
def __unicode__(self):
return self.get_state_display()
def natural_key(self):
return (self.state,)
class Region(models.Model):
name = models.CharField(max_length=255, unique=True)
coordinator = models.ForeignKey(User, null=True, blank=True)
is_us = models.BooleanField('Is a US region')
countries = models.ManyToManyField(Country)
states = models.ManyToManyField(State, blank=True)
class Meta:
ordering = ('name',)
def __unicode__(self):
return self.name
每个用户都有限定的轮廓(部分)如下:
class UserProfile(models.Model):
user = models.OneToOneField(User, related_name='user_profile')
city = models.CharField(max_length=255)
country = CountryField()
state = USStateField(_(u'US only (determines user's region)'), blank=True, null=True)
我想按地区过滤一堆用户对象。所以我有
region = Region.objects.filter(id=self.request.GET['filter_region'])
if len(region) == 0:
raise Exception("Region not found for filter")
if len(region) > 1:
raise Exception("Multiple regions found for filter?")
region = region[0]
queryset = queryset.filter(user_profile__country__in=region.countries.all)
不幸的是,这返回一个空的查询集。我怀疑它与“国家”模式中有一个“国家”字段(可怕的模棱两可的命名,我知道,最初不是我的代码)有关,而且我只按“国家”模式进行过滤,而不是其中的“国家”字段。 (这有道理吗?)
如何过滤ManyToMany字段的子字段?