title: Django Rest Framework Nested Different Serializer Saving Problem
body: <p>I have Category and Product Models. I have created 2 serializers for each model. When i want to add a new product i send this json: {&quot;name&quot;:&quot;name&quot;,&quot;price&quot;:1,&quot;category&quot;:{&quot;id&quot;:1}} but django gives error and says that i need to specify category name too. I have already given id so why do i have to give category name too (category that has id 1 already exists. I am trying to add new product to this category )?. If i make name field of category not required django doesn't give error. But when i want to add new category it doesn't give error if i don't specify name field in json. I want django to give &quot;name required&quot; error when i try to add new category but i don't want it to give error when i try to add new product. If i make category read_only it doesn't update category_id of product when i want to update a product.</p>
  <pre><code>class Product(models.Model):
      name=models.CharField(max_length=32)
      price=models.FloatField()
      category=models.ForeignKey(&quot;Category&quot;,on_delete=models.CASCADE)
  
  class Category(models.Model):
      name=models.CharField(max_length=32)
  
  class CategorySerializer(ModelSerializer):
      class Meta:
          model=Category
          fields=&quot;__all__&quot;
  
  class ProductSerializer(ModelSerializer):
      class Meta:
          model=Product
          fields=&quot;__all__&quot;
      category=CategorySerializer()
  </code></pre>