How do I save an object using serializer from another serializer in django rest? - django-rest-framework

Question

I have two models, a parent and it's items
class Parent(models.Model):
#fields
class ParentItems(models.Model):
parentId = #parentId
#fields
and want to create method POST parent/ with ParentItems included, like
{
"parentField": "value",
"parentItems": [
{
"parentItemsField": "value"
}
]
}
So I create Parent view using ModelViewSet and then the serializer:
class ParentItemSerializer(serializers.ModelSerializer):
#serializer
class ParentSerializer(serializers.ModelSerializer):
parentItems = ParentItemSerializer(many=True, required=True, write_only=True)
def _createParentItems(self, parentItem, parent):
for item in parentItem:
item['parent'] = parent.id
parentItemSerializer = ParentItemSerializer(data=item)
if parentItemSerializer.is_valid(raise_exception=True):
itemSerializer.save()
def create(self, validated_data):
with transaction.atomic():
parentItems = validated_data.pop('parentItems')
createdData = super(ParentSerializer, self).create(validated_data)
# create the parent item
self._createParentItems(parentItems, createdData)
return createdData
I add parentItems field in ParentSerializer, inside the create method I pop the parentItems and pass it into _createParentItems to create the items.
but this doesn't work, the parentItems is already an object. when I call parentItemSerializer.is_valid(raise_exception=True) it errors.
How do I save an object from another serializer in django rest?
should I use another serializer field?
Tried using OrderedDict, it doesn't work, it didn't pass the items to validated_data

Answer 1

First change your model like the following code. Then you can use serializer as I wrote for you.
class Parent(models.Model):
#fields
class ParentItem(models.Model):
parent = models.ForeignKey(Parent, on_delete=models.CASCADE)
# other fields
class ParentItemSerializer(ModelSerializer):
class Meta:
model = ParentItem
fields = ('field1', ...)
def create(self, validated_data):
ParentItem.objects.create(field1=validated_data['field2'],...)
return validated_data
class Parent(ModelSerializer):
parentItems = ParentIremSerializer(many=True)
class Meta:
model=Parent
fields = ('parentItems', 'other fields',...)
def create(self, validated_data):
parent = Parent('field1'=validated_data['field1'])
parent.save()
parentItemsList = validate_data.pop('parentItems')
parentItemSer = ParentItemSerialzer(data=parentItemsList,many=True)
if parentItemSer.is_valid():
parentItemSer.save()
return validated_data