我有一个模型如下:
class Vote(models.Model):
vote_type = models.BooleanField()
voted_by = models.ForeignKey(User, related_name='voted_by')
voted_for = models.OneToOneField(User, related_name='voted_for')
article = models.ForeignKey(Article, null=True, blank=True)
dtobject = models.DateTimeField(auto_now_add=True)
我想确保用户只能为一个对象投票一次。因此,在我看来,我会执行以下操作:
v = Vote.objects.get_or_create(
vote_type = vtype.get(field_name),
voted_by_id = request.user.id,
voted_for_id = mobj.shared_by_id,
shared_object_id = oid
)
它第一次运行良好,但是当已有投票时,我得到一个完整性错误,原因很明显。鉴于上述模型和观点,确保对象未被投票的好方法是什么?