限制每个用户一次约会

Question

我正在努力让用户只能安排一次约会。这里我正在修改保存方法。我想弄清楚的是如何查看该用户是否已经有约会。

def save(self, *args, **kwargs):
    if Appointment.objects.filter(owner=user_pk).exists() and not self.pk:
        # if you'll not check for self.pk
        # then error will also raised in update of exists model
        raise ValidationError('You have already scheduled an appointment.')
    return super(Appointment, self).save(*args, **kwargs)

在我的 views.py 中，如果与该用户的约会已经存在，我已经有一些会引发错误的东西。但我认为这还不够，模型级别应该有一些东西。

appointments = Appointment.objects.filter(owner=request.user)
    if appointments.exists():
        raise PermissionDenied('You have already scheduled an appointment.')

Answer 1

我不会让您的视图处理该逻辑，而是将数据库关系更改为OneToOneField。使该字段可以为空，因此您可以依靠 django 的 db 模块来维护与该字段的关系完整性

如源代码所述：

A OneToOneField is essentially the same as a ForeignKey, with the exception
that it always carries a "unique" constraint with it and the reverse
relation always returns the object pointed to (since there will only ever
be one), rather than returning a list.

Answer 2

self 对象将owner 属性设置为当前用户，因此您可以使用self.owner 访问它：

def save(self, *args, **kwargs):
    if Appointment.objects.filter(owner=self.owner).exists() and not self.pk:
    ...