Python 如何创建一个；入住/退房；有时间戳的系统？

我有一个类似于签入/签出方式的应用程序。人们只需输入他们的ID、区域，然后单击Checkin，它就会将时间戳和他们的信息发送到db。还有一个“签出”按钮，目前什么也不做。它的工作原理是，一旦用户填写表单并提交，它将执行以下操作之一：

根据输入的ID和区域查找上一个签入条目，并将签出从NULL更新为timestamp

如果该人员忘记以前签入，那么它将创建一个新记录，其中只包含签出时间戳和ID/区域

我认为通过匹配ID和区域来找到用户会更好，因为同一个人一天可以在不同区域签入/签出几次，因此仅通过ID匹配可能会导致程序在某一点更新错误字段的问题

型号.py

class WorkArea(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name


class StationNumber(models.Model):
    work_area = models.ForeignKey(WorkArea, on_delete=models.CASCADE)
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name


class EmployeeWorkAreaLog(TimeStampedModel, SoftDeleteModel, models.Model):
    employee_number = models.IntegerField(max_length=50, help_text="Employee #", blank=False)
    work_area = models.ForeignKey(WorkArea, on_delete=models.SET_NULL, null=True, blank=False, help_text="Work Area", related_name="work_area")
    station_number = models.ForeignKey(StationNumber, on_delete=models.SET_NULL, null=True, help_text="Station", related_name="stations", blank=True)
    time_in = models.DateTimeField(auto_now_add=True, help_text="Time in", null=True, blank=True)
    time_out = models.DateTimeField(blank=True, help_text="Time out", null=True)

    def __str__(self):
        return self.employee_number

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

    def form_valid(self, form):
        form.save()
        return HttpResponseRedirect(self.request.path_info)


def load_stations(request):
    work_area_id = request.GET.get('work_area')
    stations = StationNumber.objects.filter(work_area_id=work_area_id).order_by('name')
    return render(request, 'operations/station_number_dropdown_options.html', {'stations': stations})

forms.py

class WorkArea(models.Model):
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name


class StationNumber(models.Model):
    work_area = models.ForeignKey(WorkArea, on_delete=models.CASCADE)
    name = models.CharField(max_length=50)

    def __str__(self):
        return self.name


class EmployeeWorkAreaLog(TimeStampedModel, SoftDeleteModel, models.Model):
    employee_number = models.IntegerField(max_length=50, help_text="Employee #", blank=False)
    work_area = models.ForeignKey(WorkArea, on_delete=models.SET_NULL, null=True, blank=False, help_text="Work Area", related_name="work_area")
    station_number = models.ForeignKey(StationNumber, on_delete=models.SET_NULL, null=True, help_text="Station", related_name="stations", blank=True)
    time_in = models.DateTimeField(auto_now_add=True, help_text="Time in", null=True, blank=True)
    time_out = models.DateTimeField(blank=True, help_text="Time out", null=True)

    def __str__(self):
        return self.employee_number

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

    def form_valid(self, form):
        form.save()
        return HttpResponseRedirect(self.request.path_info)


def load_stations(request):
    work_area_id = request.GET.get('work_area')
    stations = StationNumber.objects.filter(work_area_id=work_area_id).order_by('name')
    return render(request, 'operations/station_number_dropdown_options.html', {'stations': stations})

我想我的问题更倾向于，我怎样才能实现这样的东西

而且，当前签入会在提交时自动保存时间戳，但在按下签出区域按钮时不应更改时间戳，因为这会破坏其用途。

l_userID=int（）
l_userID = int(<feed the user id>)
l_areaID = <feed the area id>
l_stationId  =<feed the station id>

l_objLogEntry = EmployeeWorkAreaLog.objects.filter(employee_number=l_userID,\
                                                   work_area__id = l_areaID,\
                                                   station_number__id = l_stationId)\
                                           .exclude(time_out__isnull=True,\
                                                    time_out__exact='')
if len(l_objLogEntry) == 0:
    #no login entry
elif len(l_objLogEntry) == 1:
    #update the timestamp
elif len(l_objLogEntry) > 1:
    #multiple open entries, do whatever

l_区域ID=
l_站ID=
l_objLogEntry=EmployeeWorkAreaLog.objects.filter（employee_number=l_userID\
工作区id=l区id\
车站编号（id=l车站id）\
.exclude（time\u out\u isnull=True\
超时（精确=“”）
如果len（l_objLogEntry）==0：
#没有登录条目
elif len（l_objLogEntry）=1：
#更新时间戳
elif len（l_objLogEntry）>1：
#多个打开的条目，执行任何操作