Django - 如何根据多个字段编辑数据库中的特定行？

Question

So, I'm fairly new to this and haven't had time to sit down and do proper learning.

What I'm trying to eventually achieve is modifying a timestamp that is initially NULL to the current time, based on employee # and work area. The idea behind this, is a "check-in/check-out" system.

First the user enters # and work area and when they "Enter", an entry is created in the database with the #, work area, time in, and a "time out" that is set to NULL. Once they're done, they'd just enter their # again, work area, and "Leave" and this should look for the last entry with NULL in time out, and same # and work area and update the time out to the new timestamp. In the case this doesn't exist then it would create a new entry but alert the user.

forms.py

class WarehouseForm(forms.Form):
    class Meta:
        model = EmployeeWorkAreaLog
        fields = ('employee_number', 'work_area', 'station_number')

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['station_number'].queryset = StationNumber.objects.none()

        if 'work_area' in self.data:
            try:
                work_area_id = int(self.data.get('work_area'))
                self.fields['station_number'].queryset = StationNumber.objects.filter(work_area_id=work_area_id).order_by('name')
            except (ValueError, TypeError):
                pass
        elif self.instance.pk:
            self.fields['station_number'].queryset = self.instance.work_area.stations.order_by('name')

models.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

views.py

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


    def form_valid(self, form):
        if 'enter_area' in self.request.POST:
            form.save()
            return HttpResponseRedirect(self.request.path_info)
        elif 'leave_area' in self.request.POST:
            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})

Answer 1

You can filter your EmployeeWorkAreaLog model like this:

employee_log = EmployeeWorkAreaLog.objects.filter(employee_number=1234,work_area__name="East_Bay",station_number=1,time_out__isnull=True).first()
if not employee_log:
    # create new entry and alert user
else:
    employee_log.timeout = current_date_time
    employee_log.save()