[Django]-Django Model: How to only access fields related to a specific user from another model

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1👍

✅

It depends if customers should be allowed to have multiple addresses (like in most online shops). In that case the User and Address models look pretty good!

Django Admin can be a bit tricky. But that’s just the nature of the flow, because the moment you open the "Create Order Page" the server has no idea what user you will pick, and therefore does not know which address it should filter. You would have to use ajax to get to your goal, but I can propose something different…

The question is why did you add another address field to the Order? Don’t get me wrong, it’s the right way actually. But…

What if the user orders something, changes his address object and looks back at the order history?

Actually you COULD drop the address-foreignkey on the order and you’ll still be able to access the current customer address on any order, by:

some_order = Order.objects.first()
customer = some_order.customer

# As defined in your model, one customer can have many addresses. For now just access the "latest" one
customers_address = customer.address_set.last()

But the order history would still be messy… now its even worse. Whenever the customer adds or changes the address, the order history would show wrong values.

To prevent this, you could leave the foreign key, prevent the address_id from being edited (read_only field), prevent the related address object from being edited, and add a flag if the address is visible to the user or soft-deleted.

You should do some research about read_only fields, editable and overriding model methods

But to keep things a bit more simple, lets just change the Order->address field to be a Charfield instead of a foreign key. You won’t need to show an editable field inside the admin anymore and instead let the user have his default address.

class Order(models.Model):
    order = CharField(max_length=400,blank=False,null=False)
    customer = models.ForeignKey(User,on_delete=models.SET_NULL, null=True)
    shipping_address = models.CharField(max_length=500, editable=False)

    def save(self, *args, **kwargs):
        # You can use this field to stringify even more complex objects
        # Again, last() is not the right way in the end but you could have a specific field on the customer: preferred_address
        self.shipping_address = self.customer.address_set.last().address
        super().save(*args, **kwargs)
👤nOperator

2👍

You can not filter this in the models. You will need to do that by the form layer.

We can implement this with:

class MyForm(forms.ModelForm):
    
    def __init__(self, *args, user=None, **kwargs):
        super().__init__(*args, **kwargs)
        self.fields['address'].queryset = Address.objects.filter(user=user)

    class Meta:
        model = Order
        fields = ['address']

then in the view, we can construct a form with the logged in user as user:

from django.contrib.auth.decorators import login_required

@login_required
def my_view(request):
    if request.method == 'POST':
        form = MyForm(request.POST, user=request.user)
        if form.is_valid():
            form.instance.user = request.user
            # set the order number to the instance
            form.save()
            return redirect('name-of-some-view')
    else:
        form = MyForm(user=request.user)
    return render(request, 'name-of-some-template.html', {'form': form})
👤willeM_ Van Onsem

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