Django Rest Framework: implementing Unique Constraints on Related Model Fields
I'm a bit lost with I'm implementing a Django Rest Framework (DRF) API where I need to enforce unique constraints on fields of a related model. My current setup involves a `UserProfile` model that has a foreign key to a `User` model and additional fields like `bio` and `website`. I want to ensure that the `website` field is unique across all user profiles, but I'm running into issues with the validation. ```python # models.py from django.db import models from django.contrib.auth.models import User class UserProfile(models.Model): user = models.OneToOneField(User, on_delete=models.CASCADE) bio = models.TextField(blank=True) website = models.URLField(unique=True, blank=True) ``` When I try to create a new user profile with a duplicate website, I expect a validation behavior. However, I'm seeing an `IntegrityError` instead when saving to the database, which doesn’t seem to be caught by DRF. Here's what my view looks like: ```python # views.py from rest_framework import viewsets from rest_framework.response import Response from rest_framework import status from .models import UserProfile from .serializers import UserProfileSerializer class UserProfileViewSet(viewsets.ModelViewSet): queryset = UserProfile.objects.all() serializer_class = UserProfileSerializer def create(self, request, *args, **kwargs): serializer = self.get_serializer(data=request.data) if serializer.is_valid(): self.perform_create(serializer) return Response(serializer.data, status=status.HTTP_201_CREATED) return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST) ``` I’ve tried adding a custom validation method in the serializer to handle duplicates: ```python # serializers.py from rest_framework import serializers from .models import UserProfile class UserProfileSerializer(serializers.ModelSerializer): class Meta: model = UserProfile fields = ['user', 'bio', 'website'] def validate_website(self, value): if UserProfile.objects.filter(website=value).exists(): raise serializers.ValidationError('This website is already taken.') return value ``` Now, when I attempt to create a user profile with an existing website, I get the validation behavior as expected, but the integrity behavior still occurs when I try to save it afterward. I suspect that the database layer is catching the integrity violation before the serializer's validation runs. What’s the best way to handle this situation to ensure the data integrity and user experience are both maintained? Any insights or alternative approaches would be greatly appreciated!