How to save multiple object in a single POST request - django

Question

I am new to DRF
I am saving a user details and his pets details .
Here is the model
class Users(models.Model):
id = models.AutoField(primary_key=True)
first_name = models.CharField(max_length=255, blank=True)
last_name = models.CharField(max_length=255, blank=True)
job = models.CharField(max_length=255, blank=True)
age = models.CharField(max_length=255, blank=True)
class PetDetails(models.Model):
user = models.ForeignKey(
Users, on_delete=models.CASCADE, blank=True, null=True)
pet_name = models.CharField(max_length=255, blank=True)
pet_color = models.CharField(max_length=255, blank=True)
pet_category = models.CharField(max_length=255, blank=True)
In this I need to save both user and his pets in a single Post request.
So I created a serializer like this
class UserCreateSerializer(ModelSerializer):
pet = PetDetailCreateSerializer(many=True)
class Meta:
model = Users
fields = ['first_name','last_name','job','age', 'pet']
def create(self, validated_data):
pets_data = validated_data.pop('pet')
user_obj = Users.objects.create(**validated_data)
for pet in pets_data:
PetDetails.objects.create(user=user_obj, **pet)
return user_obj
The issue I am facing is if a single person can have multiple pets.
For Example John is a user and he having two Pets.
So in this cases two users object will creating .How to resolve this
OR is there any other methods for handling this
My views is
class UserCreateView (CreateAPIView):
serializer_class = UserCreateSerializer

Answer 1

One way is to check if user already exists by using get_or_create:
user_obj = Users.objects.get_or_create(**audit_data)
But better way, I think, is to create user with multiple pets instead:
class UserCreateSerializer(ModelSerializer):
petdetails_set = PetDetailCreateSerializer(many=True)
class Meta:
model = Users
fields = ['first_name','last_name','job','age', 'petdetails_set']
def create(self, validated_data):
pets_data = validated_data.pop('pet')
user_obj = User.objects.create(**validated_data)
for pet in pets_data:
PetDetails.objects.create(user=user_obj, **pet)
return user_obj
Also, I advice to use separate endpoints/serializers for user creation.