如何访问Django中第二个最近的时间戳字段条目？

Question

我有一个模型的表单，它记录了进入/离开的时间。我正在尝试添加约束以使数据更准确

当前，当有人“进入”时，它会创建一个记录，将时间保存在时间戳中，然后重定向。如果此人再次尝试输入，它将创建一个带有新时间戳的新记录

我现在想补充的是，如果此人有一个没有退出时间戳的前一个条目，那么该记录（这将是第二个到最后一个最近的条目）将通过更新time\u exceptions字段到“N”来标记

当前，它将所有字段更改为“N”，而不管是否有出口，如下所示

class EnterExitArea(CreateView):
    model = EmployeeWorkAreaLog
    template_name = "operations/enter_exit_area.html"
    form_class = WarehouseForm

    def form_valid(self, form):
        emp_num = form.cleaned_data['employee_number']
        area = form.cleaned_data['work_area']
        station = form.cleaned_data['station_number']

        if 'enter_area' in self.request.POST:
            form.save()
            EmployeeWorkAreaLog.objects.filter((Q(employee_number=emp_num) & Q(work_area=area) & Q(time_out__isnull=True) & Q(time_in__isnull=True)) & (Q(station_number=station) | Q(station_number__isnull=True))).update(time_in=datetime.now())

            if EmployeeWorkAreaLog.objects.filter(Q(employee_number=emp_num)).count() > 1:
                EmployeeWorkAreaLog.objects.filter((Q(employee_number=emp_num) & Q(work_area=area) & Q(time_out__isnull=True)) & (Q(station_number=station) | Q(station_number__isnull=True))).update(time_exceptions='N')

            return HttpResponseRedirect(self.request.path_info)

我尝试了以下操作，但是得到了一个expected string or bytes-like object，虽然它在崩溃之前仍然创建了一个新记录，但它不会将第二个到最近一个的time\u异常更新为N

        if 'enter_area' in self.request.POST:
            form.save()
            EmployeeWorkAreaLog.objects.filter((Q(employee_number=emp_num) & Q(work_area=area) & Q(time_out__isnull=True) & Q(time_in__isnull=True)) & (Q(station_number=station) | Q(station_number__isnull=True))).update(time_in=datetime.now())

            if EmployeeWorkAreaLog.objects.filter(Q(employee_number=emp_num) & Q(time_out__isnull=True) & Q(time_exceptions="")).count() > 1:
                recent = EmployeeWorkAreaLog.objects.filter(employee_number=emp_num, work_area=area, station_number=station, time_out__isnull=True).order_by('-time_in')[1]

                EmployeeWorkAreaLog.objects.filter((Q(employee_number=emp_num) & Q(work_area=area) & Q(time_in=recent) & Q(time_out__isnull=True)) & (Q(station_number=station) | Q(station_number__isnull=True))).update(time_exceptions='N')

            return HttpResponseRedirect(self.request.path_info)

如何获取第二个最近的条目（如果有），以便将time\u exceptions字段更新为“N”

回溯：

Internal Server Error: /operations/enter-exit-area/
Traceback (most recent call last):
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\core\handlers\exception.py", line 34, in inner
    response = get_response(request)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\core\handlers\base.py", line 126, in _get_response
    response = self.process_exception_by_middleware(e, request)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\core\handlers\base.py", line 124, in _get_response
   response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\views\generic\base.py", line 68, in view
    return self.dispatch(request, *args, **kwargs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\views\generic\base.py", line 88, in dispatch
    return handler(request, *args, **kwargs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\views\generic\edit.py", line 172, in post
    return super().post(request, *args, **kwargs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\views\generic\edit.py", line 142, in post
    return self.form_valid(form)
  File "C:\Users\mkusneco\apps.rsrgroup.com\apps\operations\views.py", line 45, in form_valid
    Q(station_number=station) | Q(station_number__isnull=True))).update(time_exceptions='N')
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\manager.py", line 82, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\query.py", line 844, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\query.py", line 862, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\sql\query.py", line 1263, in add_q
    clause, _ = self._add_q(q_object, self.used_aliases)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\sql\query.py", line 1281, in _add_q
    current_negated, allow_joins, split_subq)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\sql\query.py", line 1287, in _add_q
    split_subq=split_subq,
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\sql\query.py", line 1225, in build_filter
    condition = self.build_lookup(lookups, col, value)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\sql\query.py", line 1096, in build_lookup
    lookup = lookup_class(lhs, rhs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\lookups.py", line 20, in __init__
    self.rhs = self.get_prep_lookup()
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\lookups.py", line 70, in get_prep_lookup
    return self.lhs.output_field.get_prep_value(self.rhs)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\fields\__init__.py", line 1408, in get_prep_value
    value = super().get_prep_value(value)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\fields\__init__.py", line 1268, in get_prep_value
    return self.to_python(value)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\db\models\fields\__init__.py", line 1369, in to_python
    parsed = parse_datetime(value)
  File "C:\Users\mkusneco\appsve\lib\site-packages\django\utils\dateparse.py", line 106, in parse_datetime
    match = datetime_re.match(value)
TypeError: expected string or bytes-like object