Item id and order_variants id stored as null while creating an order in Django rest framework

Question

I created an order-create API where I am creating order by creating order items objects and billing details objects at the same time. Everything was working fine a few days back, but when I try today to call the order API from the Postman, item id and order_variants are stored as null in the database, although I am passing item id and variants id and the objects exist as well.

I am sending raw JSON data like this.

I have sent the item id and order_varaints id as shown above. But the result I get is null as shown below.

My models:

class Order(models.Model):
    ORDER_STATUS = (
        ('To_Ship', 'To Ship',),
        ('Shipped', 'Shipped',),
        ('Delivered', 'Delivered',),
        ('Cancelled', 'Cancelled',),
    )
    user = models.ForeignKey(User, on_delete=models.CASCADE, blank=True)
    #items = models.ManyToManyField(OrderItem,blank=True, null=True,related_name="order_items")
    #start_date = models.DateTimeField(auto_now_add=True)
    order_status = models.CharField(max_length=50,choices=ORDER_STATUS,default='To_Ship')

    ordered_date = models.DateTimeField(auto_now_add=True)
    ordered = models.BooleanField(default=False)
    total_price = models.CharField(max_length=50,blank=True,null=True)
    #billing_details = models.OneToOneField('BillingDetails',on_delete=models.CASCADE,null=True,blank=True,related_name="order")

    def __str__(self):
        return self.user.email 

class OrderItem(models.Model):
    #user = models.ForeignKey(User,on_delete=models.CASCADE, blank=True)
    order = models.ForeignKey(Order,on_delete=models.CASCADE, blank=True,null=True,related_name='order_items')
    item = models.ForeignKey(Product, on_delete=models.CASCADE,blank=True, null=True)
    order_variants = models.ForeignKey(Variants,on_delete=models.CASCADE,blank=True,null=True)
    quantity = models.IntegerField(default=1)    
    total_item_price = models.PositiveIntegerField(blank=True,null=True,)
    

    def __str__(self):
        return f"{self.quantity} items of {self.item} of {self.order.user}"

    class Meta:
        verbose_name_plural = "Cart Items"
        ordering = ('-id',)

class BillingDetails(models.Model):
    
    user = models.ForeignKey(User, on_delete=models.CASCADE, blank=True)
    order = models.OneToOneField(Order, on_delete=models.CASCADE, blank=True, null=True, related_name='billing_details')
    first_name = models.CharField(max_length=50,blank=True,null=True)
    last_name = models.CharField(max_length=50, blank=True, null=True)
    email = models.EmailField(blank=True, null=True)
    phone = models.CharField(max_length=50,blank=True,null=True)    
    city = models.CharField(max_length=50,blank=True,null=True)
    address = models.CharField(max_length=100,blank=True,null=True)

My views:

class AddtoOrderItemView(ListCreateAPIView):
    permission_classes = [IsAuthenticated]
    queryset = Order.objects.all()
    serializer_class = OrderSerializer

My serializers:

class OrderSerializer(serializers.ModelSerializer):

    billing_details = BillingDetailsSerializer()
    order_items = OrderItemSerializer(many=True)
    user = serializers.PrimaryKeyRelatedField(read_only=True, default=serializers.CurrentUserDefault())
    class Meta:
        model = Order
        fields = ['id','user','ordered_date','order_status', 'ordered', 'order_items', 'total_price','billing_details']
        # depth = 1    

    def create(self, validated_data):
        user = self.context['request'].user
        if not user.is_seller:
            order_items = validated_data.pop('order_items')
            billing_details = validated_data.pop('billing_details')
            order = Order.objects.create(user=user,**validated_data)
            BillingDetails.objects.create(user=user,order=order,**billing_details)
            for order_items in order_items:
                OrderItem.objects.create(order=order,**order_items)
        
        return order
    else:
        raise serializers.ValidationError("This is not a customer account.Please login as customer')
   

Answer 1

It was because of the depth = 1 that was assigned to OrderItemSerializer. If removed, it will work just fine.

My updated serializers:

class OrderItemSerializer(serializers.ModelSerializer):    
    class Meta:
        model = OrderItem
        fields = ['id','item','order_variants','order', 'quantity','order_item_status','total_item_price']
        # depth = 1