Insert data on OneToOneField using django-rest-framework

Question

I am new to this django-rest-framework, my problem is how am I going to insert a data with one-to-one relationship in the views.py. I can do the normal way of inserting data like the one below,

def post(self, request,format=None):
  p = Person()
  p.firstname = "John"
  p.middlename = "K"
  p.lastname = "Rambo"
  p.save()
  e = Employee()
  e.code = "emp-002"
  e.person_id = p.id
  e.save()

I cannot do the approach above because I want to learn more about DRF.

To give you more idea please see below:

I have this model

class Person(models.Model):
  firstname = models.CharField(max_length=150, default="")
  middlename = models.CharField(max_length=150, default="")
  lastname = models.CharField(max_length=150, default="")
class Employee(models.Model):
  person = models.OneToOneField(Person, on_delete=models.CASCADE,primary_key=True)
  code = models.CharField(max_length=100, default="")

I have this serializer

class PersonSer(serializers.ModelSerializer):
  class Meta:
    model = Person
    fields = ( 
      'id', 
      'firstname', 
      'middlename', 
      'lastname',)
class EmployeeSer(serializers.ModelSerializer):
  person = PersonSer()
  class Meta:
    model = Employee
    fields = ('code','person')

I have this view

class SaveData(APIView):
  @transaction.atomic
  def post(self,request, format=None):
    p = PersonSer(data=request.data)
    if p.is_valid():
      p.save()
    request.data['person'] = p.data['id']
    request.data['code'] = "Emp-"+str(p.data['id'])
    """
      I expect request.data now equal to
      {
        'person' : 102, # we assume the newly created person id == 102
        'code' : 'Emp-102',
        'firstname' : 'John',
        'middlename' : 'K.',
        'lastname' : 'Rambo'
      }
    """

    es = EmployeeSer(data=request.data)
    if es.is_valid():
      es.save()
    else:
      print(es.errors) # {'person': [ErrorDetail(string='This field is required.', code='required')]}
    """
    I also tried this,
    es = EmployeeSer(data={'person' : p.data, 'code' : 'Sample code'})
    if es.is_valid():
      es.save()
    else:
      print(es.errors) #{'person': {'fullname': [ErrorDetail(string='This field may not be blank.',code='blank')], ]}}
    """
    return Response({'message':'okay'})

The request.data is a formData, the value is

{
  'firstname' : 'John',
  'middlename' : 'K.',
  'lastname' : 'Rambo'
}

Answer 1

You can override the create method of the PersonSer to achieve this.

class PersonSer(serializers.ModelSerializer):

  ...
  def create(self, validated_data):
      person = Person.objects.create(**validated_data)
      Employee.objects.create(person=person, code=f"Emp-{person.id}")
      return person

And you can simplify your view to:

...
@transaction.atomic
  def post(self,request, format=None):
    p = PersonSer(data=request.data)
    p.is_valid(raise_exception=True)
    p.save()
    return Response({'message':'okay'})
...

raise_expection=True will cause serializer to raise ValidationError exception if there are validation errors.