[FIXED] Generic Delete view

Issue

I have a model for booking table that has a onetoone relation with another model table. And i want to be able to change the value of a field of table before deleting the model booking.

Here is my BookingTable model...

class BookingTable(models.Model):
    table = models.OneToOneField(Table, on_delete=models.CASCADE)
    user = models.OneToOneField(get_user_model(), on_delete=models.CASCADE)
    time = models.TimeField(auto_now_add=True)
    
    def __str__(self) -> str:
        return self.user.get_username() + " - " + self.table.name
    
    def get_absolute_url(self):
        return reverse("list_tables")

Here is my Table model...

class Table(models.Model):
    name = models.CharField(max_length=100, unique=True)
    ocupation_status = models.BooleanField(default=False)
    size = models.PositiveIntegerField()
    image = models.ImageField(upload_to='static/media/images/', default='static/media/images/default.jfif')
    description = models.TextField(null=False, blank=False, default="This is a very beatiful table")
    
    def __str__(self) -> str:
        return self.name[:50]
    
    def get_absolute_url(self):
        return reverse("list_tables")

And here is my view

class CancelBookingView(DeleteView):
    model = BookingTable
    template_name = 'cancel_booking.html'
    success_url = reverse_lazy('list_tables')
    

    def form_valid(self, form):
        form.instance.table.ocupation_status = False
        return super().form_valid(form)
    

I tried to use form_valid and accessing the table field using the instance attr but it gave an error saying that form has no attr instance.

class CancelBookingView(DeleteView):
    model = BookingTable
    template_name = 'cancel_booking.html'
    success_url = reverse_lazy('list_tables')
    

    def form_valid(self, form):
        form.instance.table.ocupation_status = False
        return super().form_valid(form)

Solution

You were quite close, you use the object, so:

class CancelBookingView(DeleteView):
    model = BookingTable
    template_name = 'cancel_booking.html'
    success_url = reverse_lazy('list_tables')

    def form_valid(self, form):
        table = self.object.table
        table.ocupation_status = False
        table.save()
        return super().form_valid(form)

Answered By - willeM_ Van Onsem