Django - 使用 TimeField() 作为外键

Question

我有一个 Meeting 模型，它的 meeting_hour 从 MeetingHour 模型中获取其值。但是提交表单后出现如下错误：

Cannot assign "datetime.time(14, 0)": "Meeting.meeting_hour" must be a "MeetingHour" instance.

我知道它是因为我没有正确使用MeetingHour 作为外键，但不知道如何修复它。这是我的代码：

models.py

class MeetingHour(models.Model):
    hour = models.TimeField()

    def __str__(self):
        return self.hour

class Meeting(models.Model):
    participant_name = models.CharField(max_length=50)
    participant_email = models.EmailField(max_length=50)
    meeting_date = models.DateField()
    meeting_hour = models.ForeignKey(MeetingHour, on_delete = models.CASCADE)
    is_scheduled = models.BooleanField(default=False)

    def __str__(self):
        return self.participant_name

views.py

def index(request):
    context = {
        'schedules': Meeting.objects.all()
    }
    if request.method == "POST":
        participant_name = request.POST.get('name')
        participant_email = request.POST.get('email')
        meeting_date = str(request.POST.get('date'))
        meeting_hour = str(request.POST.get('hour'))
        converted_meeting_date = datetime.strptime(request.POST.get('date'), "%Y-%m-%d").date() if meeting_date else None
        converted_meeting_hour = datetime.strptime(request.POST.get('hour'), "%H:%M").time() if meeting_hour else None
        subject = 'Meeting'
        message = f'Hi, {participant_name} ! \nYour meeting date: {meeting_date}, hour: {meeting_hour}'
        from_email = settings.SERVER_EMAIL
        recipient_list = [participant_email]
        send_mail(subject, message, from_email, recipient_list)
        if request.POST.get('email'):
            Meeting.objects.create(
                participant_name = request.POST.get('name'),
                participant_email = request.POST.get('email'),
                meeting_date = converted_meeting_date,
                meeting_hour = converted_meeting_hour,
                is_scheduled = True
            )
    return render(request, 'index.html', context)

Answer 1

您需要使用MeetingHour 实例作为外键。此外，您必须在致电send_email 之前检查email：

def index(request):
    context = {
        'schedules': Meeting.objects.all()
    }
    if request.method == "POST" and request.POST.get('email'):
        participant_name = request.POST.get('name')
        participant_email = request.POST.get('email')
        meeting_date = str(request.POST.get('date'))
        meeting_hour = str(request.POST.get('hour'))
        converted_meeting_date = datetime.strptime(request.POST.get('date'), "%Y-%m-%d").date() if meeting_date else None
        converted_meeting_hour = datetime.strptime(request.POST.get('hour'), "%H:%M").time() if meeting_hour else None
        subject = 'Meeting'
        message = f'Hi, {participant_name} ! \nYour meeting date: {meeting_date}, hour: {meeting_hour}'
        from_email = settings.SERVER_EMAIL
        recipient_list = [participant_email]
        send_mail(subject, message, from_email, recipient_list)
        hour, _ = MeetingHour.objects.get_or_create(hour = converted_meeting_hour)
        Meeting.objects.create(
            participant_name = request.POST.get('name'),
            participant_email = request.POST.get('email'),
            meeting_date = converted_meeting_date,
            meeting_hour = hour,
            is_scheduled = True
        )
    return render(request, 'index.html', context)

Answer 2

由于meeting_hour 是您的MeetingHour 模型的ForeignKey，因此您必须从MeetingHour 表中获取一个对象并将其保存到您的Meeting 模型的meeting_hour 字段中。

例如：

meeting_hour = MeetingHour.objects.get(hour=converted_meeting_hour)

Meeting.objects.create(..., .., .., meeting_hour=meeting_hour)

如果您从数据库的角度考虑，Meeting 模型中的meeting_hour 字段只是MeetingHour 字段的id。这意味着 Django 需要通过对象实例或 id 对该字段的实际引用，以便在数据库中存储正确的值。