Python Django基于时间的查询集提供意外响应

我的表格如下：

class Availability(models.Model):
    arena = models.ForeignKey(Arena, null=True)
    start_date = models.DateTimeField()
    end_date = models.DateTimeField()
    token = UUIDField(auto=True, unique=True, null=True)
    validity = models.DateTimeField(null=True)

def post(self, request):
    data = request.DATA
    arena = data['arena']
    start_time = datetime.datetime.strptime(data['start_time'], '%d/%m/%Y %H:%M')
    end_time = datetime.datetime.strptime(data['end_time'], '%d/%m/%Y %H:%M')
    try:
        slots = Availability.objects.filter(Q(arena__id=arena), Q(start_date__gte=start_time), Q(end_date__lte=end_time)) #Checking if there's any availability between a certain period of time at a certain arena            
        serialized = ScheduleSerializer(slots, many=True)
        return Response({
            'success': False,
            'response': serialized.data #empty array
        })
    except Availability.DoesNotExist:
        ... #Some Code

现在我在django视图中使用它，如下所示：

class Availability(models.Model):
    arena = models.ForeignKey(Arena, null=True)
    start_date = models.DateTimeField()
    end_date = models.DateTimeField()
    token = UUIDField(auto=True, unique=True, null=True)
    validity = models.DateTimeField(null=True)

def post(self, request):
    data = request.DATA
    arena = data['arena']
    start_time = datetime.datetime.strptime(data['start_time'], '%d/%m/%Y %H:%M')
    end_time = datetime.datetime.strptime(data['end_time'], '%d/%m/%Y %H:%M')
    try:
        slots = Availability.objects.filter(Q(arena__id=arena), Q(start_date__gte=start_time), Q(end_date__lte=end_time)) #Checking if there's any availability between a certain period of time at a certain arena            
        serialized = ScheduleSerializer(slots, many=True)
        return Response({
            'success': False,
            'response': serialized.data #empty array
        })
    except Availability.DoesNotExist:
        ... #Some Code

---

我的Availability表中没有对象，但是上面的查询被执行并返回一个空数组作为响应。我的问题对吗？如果没有，我该如何修复此问题？

这似乎按预期工作。您正在执行查询，但找不到与查询匹配的对象（因为没有对象）。试着这样做：

slots = Availability.objects.filter(Q(arena__id=arena), Q(start_date__gte=start_time), Q(end_date__lte=end_time)) #Checking if there's any availability between a certain period of time at a certain arena

if slots:            
    serialized = ScheduleSerializer(slots, many=True)
    return Response({
        'success': False,
        'response': serialized.data #empty array
    })
else:
    ...

---

这就是

过滤器的工作原理；它返回一个queryset，如果没有找到匹配项，则该queryset可以为空
get
引发
DoesNotExist
，但它用于获取一个实例。您可以检查插槽的
len
，如果插槽为空，则应用您想要应用的任何条件。我们还可以使用
.exists（）
检查插槽是否为空。如果需要，我们可以提出DoesNotExist错误或其他错误。