Django model 未通过外键关系使用另一个 model

Question

I'm trying to create a web app that will allow booking onto training sessions in a running club.

I've got my users app and a training_sessions app where coaches can post sessions. They include location, date, the coach taking the session and some details on what the session entails. I now want to add a facility where a logged in user can click on the session and have them booked onto it.

I've a ClubSession model:

class ClubSession(models.Model):
    location = models.CharField(max_length=200)
    coach = models.ForeignKey(CustomUser, on_delete=models.CASCADE)
    date = models.DateTimeField(default=now)
    details = models.TextField()

    def __str__(self):
        return self.location

    def get_absolute_url(self):
        return reverse('session_detail', args=[str(self.id)])

From it's used in several views to create, edit, delete, view and list all sessions:

class SessionListView(ListView):
    model = ClubSession
    template_name = 'club_sessions.html'
    context_object_name = 'all_club_sessions_list'


class SessionDetailView(DetailView):
    model = ClubSession
    template_name = 'session_detail.html'
 context_object_name = 'club_session'


class SessionCreateView(CreateView):
    model = ClubSession
    template_name = 'session_new.html'
    fields = ['location', 'coach', 'date', 'details']


class SessionUpdateView(UpdateView):
    model = ClubSession
    template_name = 'session_edit.html'
    fields = ['location', 'coach', 'date', 'details']


class SessionDeleteView(DeleteView):
    model = ClubSession
    template_name = 'session_delete.html'
    success_url = reverse_lazy('home')

I'm now trying to create a booking model with a foreign key to my user and ClubSessions models. This is what I've got:

class ClubSessionBookings(models.Model):
    athlete = models.ForeignKey(CustomUser, on_delete=models.CASCADE)
    club_sessions = models.ForeignKey(ClubSession, on_delete=models.CASCADE)

    def __str__(self):
        return self.athlete

    def get_absolute_url(self):
        return reverse('booking_session_detail', args=[str(self.id)])

I added this view:

class SessionBookingCreateView(CreateView):
    model = ClubSessionBookings
    template_name = 'session_booking_new.html'
    fields = ['athlete', 'location', 'coach', 'date', 'details']
    context_object_name = 'session_booking_new'

and this url:

path('club_sessions_booking/', SessionBookingCreateView.as_view(), name='session_booking_new')

but I see this exception: Unknown field(s) (coach, date, location, details) specified for ClubSessionBookings . I guess there's an issue with how my ClubSessionBookings model uses ClubSession as a foreign key. What have I done wrong and how do I resolve it?

Answer 1

Your ClubSessionBooking model has only two fields: athlete and club_sessions . So you are specifying wrong set of fields in SessionBookingCreateView.

If you just use these two correct fields, it should work.

But in these kind of cases, we like to put a button below the sessionDetailView like 'Register for this Session'. And when a logged in user clicks, the model is created automatically. For that maybe you collect the session Id from button click URL and logged in user from session. Then create the model on the fly instead of using a form.