django – 在qs.excude()中通过span关系评估同一个对象

可以“删除”预约,这可以通过设置“实时”字段获得.所以它们实际上并没有删除,只是处于非活动状态,这需要保持这种状态.

>>> indate = "20141225"
>>> Room.objects.exclude(
(models.Q(reservation__live=True,reservation__date_out__gt=indate) 
| models.Q(reservation__date_out__isnull=True,reservation__live=True))
)

问题陈述：上面的代码有一个令人遗憾的副作用：当有一个生命值= True的预订超出期限,并且当同一个房间的期间内有另一个预约live = False时,那个房间将被排除在外.情况并非如此：由于我要求的期间内的预订未设置为live = True,因此不应将其考虑在内.

看起来我上面的查询在通过房间预订关系进行(live = True和date_out__gt = indate)比较时没有考虑相同的预留.

问题：在exclude()中是否有一种方法可以确保在比较中考虑相同的保留？

我试着玩负模型.Q(~Models.Q)无济于事.
请注意,上面只是一个更大的查询中的代码提取(问题所在的位置).因此我不能简单地做qs.filter(reservation__live = True).移动查询以过滤而不是排除似乎不是一个选项.

编辑：根据请求添加我的简化模型,如下所示.
Edit2：添加一些解释问题的测试数据,并根据@ knbk的建议添加一个链式exclude().

class AvailableRoomManager(models.Manager):

    def available_with_Q(self,indate,outdate):
        qs = super(AvailableRoomManager,self).get_queryset()

        if indate and outdate:
            qs = qs.exclude(models.Q(reservation__date_out__gt=indate,reservation__date_in__lt=outdate,reservation__live=True)
                            | models.Q(reservation__date_out__isnull=True,reservation__date_in__isnull=False,reservation__live=True))

        elif indate and not outdate:
            qs = qs.exclude((models.Q(reservation__date_out__gt=indate,reservation__live=True)))

        return qs

    def available_with_chained_excludes(self,self).get_queryset()

        if indate and outdate:
            qs = qs.exclude(reservation__date_out__gt=indate,reservation__live=True) 
                   .exclude(reservation__date_out__isnull=True,reservation__live=True)

        elif indate and not outdate:
            qs = qs.exclude(reservation__date_out__gt=indate,reservation__live=True)

        return qs


class Room(models.Model):
    name = models.CharField(max_length=30,unique=True)

    objects = models.Manager()
    available_rooms = AvailableRoomManager()

    def __str__(self):
        return self.name


class Reservation(models.Model): 
    date_in = models.DateField()
    date_out = models.DateField(blank=True,null=True)
    room = models.ForeignKey(Room)
    live = LiveField()  # See django-livefield; to do deletion. Basically adds a field "live" to the model.

    objects = LiveManager()
    all_objects = LiveManager(include_soft_deleted=True)

当搜索周期之外存在活动(live = True)时,以及在我正在搜索的时间段内存在非活动(live！= True)时,上述exclude()语句中会弹出该问题.

一些简单的测试数据使用上述模型,显示问题所在：

# Let's make two rooms,R001 and R002
>>> room1 = Room.objects.get_or_create(name="R001")[0]
>>> room2 = Room.objects.get_or_create(name="R002")[0]

# First reservation,with no date_out,is created but then "deleted" by setting field 'live' to False
>>> res1 = Reservation.objects.get_or_create(date_in="2014-12-01",date_out=None,room=room1)[0]
>>> res1.live = False
>>> res1.save()

# Second reservation in same room is created with date_out set to Dec 15th
>>> res2 = Reservation.objects.get_or_create(date_in="2014-12-01",date_out="2014-12-15",room=room1)[0]

# Here I'd expect to have R001 listed as well... this is not the case
>>> Room.available_rooms.available_with_Q("2014-12-16","")
[<Room: R002>]
>>> Room.available_rooms.available_with_chained_excludes("2014-12-16","")
[<Room: R002>]

# As a test,when changing "deleted" res1's Room to room2,the manager does return R001
>>> res1.room = room2
>>> res1.save()
>>> Room.available_rooms.available_with_Q("2014-12-16","")
[<Room: R001>,<Room: R002>]
>>> Room.available_rooms.available_with_chained_excludes("2014-12-16",<Room: R002>]