我有一个居民,但似乎无法获得该居民所属的一组 SSA。我试过 res.ssa_set.all()
.ssas_set.all()
和 .ssa_resident_set.all()
。似乎无法管理它。通过另一个表进行反向 m2m 查找的语法是什么?
编辑:我收到“QuerySet as no attribute”错误。嗯?
class SSA(models.Model):
name = models.CharField(max_length=100)
cost_center = models.IntegerField(max_length=4)
street_num = models.CharField(max_length=9)
street_name = models.CharField(max_length=40)
suburb = models.CharField(max_length=40)
post_code = models.IntegerField(max_length=4, blank=True, null=True)
def __unicode__(self):
return self.name
class Resident(models.Model):
cris_id = models.CharField(max_length=10, primary_key=True)
first_name = models.CharField(max_length=20)
last_name = models.CharField(max_length=20)
ssas = models.ManyToManyField('SSA', through='SSA_Resident', verbose_name="SSAs")
def __unicode__(self):
return self._get_full_name()
def _get_full_name(self):
return u"%s %s" %(self.first_name, self.last_name)
full_name = property(_get_full_name)
class SSA_Resident(models.Model):
id = models.AutoField(primary_key=True)
resident = models.ForeignKey('Resident')
ssa = models.ForeignKey('SSA', verbose_name="SSA")
active = models.BooleanField(default=True)
def __unicode__(self):
return u"%s - %s" %(self.resident.full_name, self.ssa.name)
最佳答案
我试图评估一个查询集对象,而不是对象本身。在查询集上执行 get 然后查找关系集工作正常。我正在改用社区 wiki 并将其留在此处,以防其他人和我一样愚蠢。
一个工作示例:
resident = Resident.objects.filter(name='Johnny')
resident.ssa_set.all() # fail
resident = resident.get() # will fail if more than one returned by filter
resident.ssa_set.all() # works, since we're operating on an instance, not a queryset
关于python - Django Model API 通过中间表反向查找多对多关系,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/550300/