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我有三個相關的車型,如Django的子查詢問題「子查詢返回多個1行」
class City(models.Model):
name = models.CharField(max_length=200, blank=False)
country = models.ForeignKey(Country,unique=False,null=False)
def __unicode__(self):
return self.name
class Meta:
ordering = ['name']
class County(models.Model):
name = models.CharField(max_length=500, blank=False)
city = models.ForeignKey(City,unique=False,null=False)
def __unicode__(self):
return self.name
class Meta:
ordering = ['name']
class District(models.Model):
name = models.CharField(max_length=500, blank=False)
county = models.ForeignKey(County,unique=False,null=False)
def __unicode__(self):
return self.name
class Meta:
ordering = ['name']
我希望做的是讓所有的Districts
一個指定的城市。 我想:
District.objects.all().filter(county = County.objects.all().filter(city=City.objects.filter(id=4)))
然而,它給像OperationalError: (1242, 'Subquery returns more than 1 row')
錯誤,你能不能給我任何想法我怎麼能achive在Django此查詢?
謝謝
非常感謝您的幫助!我一定會瀏覽這個文檔。 – brsbilgic 2011-05-22 15:51:41