Django Rest Framework / Angular - Serialization - django

Question

I have simple models like:
class Car(models.Model):
name = models.CharField()
type = models.ForeignKey(CarTypes)
class CarTypes(models.Model):
type_name = models.CharField()
and serializers:
class CarSerializer(serializers.ModelSerializer):
class Meta:
model = Car
depth = 1
class CarTypeSerializer(serializers.ModelSerializer):
class Meta:
model = CarType
DRF send list of all Car Types to my frontend/angular app which looks like:
car_types = [
{
'id': 1,
'type_name': 'Sedan'
},
{
'id': 2,
'type_name': 'Hatchback'
}
]
I am using Car data in angular form i.e administrator would like to change data about car
<form>
<input ng-model="car.name" type="text" />
<select ng-model="car.type"
ng-options="type.type_name for type in car_types track by type.id"
name="car_type">
</select>
</form>
After submit this form angular send POST to django app which looks like:
{
'id': 1,
'name': 'Audi',
'type': {
'id': 1,
'type_name': 'Sedan'
}
}
PROBLEM
This is case when i am updating Car data.
If i change car type in selectbox my DRF serializer will change name from Sedan to i.e Hatchback instead of ascribe whole object. So Car Type Sedan will be destroyed and replaced.
New Car types will looks like:
car_types = [
{
'id': 1,
'type_name': 'Hatchback'
},
{
'id': 2,
'type_name': 'Hatchback'
}
]
(Angular send correct dict with id and name. DRF accessing only name instead of id and name to car.type)
QUESTIONS
How should I serialize and deserialize data with FK ? As a PrimaryKey then in angular connect those Primary Keys with names ? I like using depth options because i received whole dict
Maybe there is function in DRF to change data before validation which allow me to change received DICT to PK ?