Django用空的ManyToManyField选择对象

Question

考虑到以下型号,了解一个家庭,我如何选择没有买家的孩子？

class Family...

class Kid(models.Model):
    name = models.CharField(max_length=255)
    family = models.ForeignKey(Family)
    buyer = models.ManyToManyField(Buyer, blank=True, null=True)

family = get_object_or_404(Family, pk=1)
for_sale = family.kid_set.filter(buyer... this screws my child trade business

Answer 1

family.kid_set.filter(buyer__isnull=True) 应该管用.