can you give an example data which is not serialized in django

Yes, here's an example of data that is not serialized in Django:

Suppose you have a model called Person with the following fields:

class Person(models.Model):
    name = models.CharField(max_length=100)
    age = models.IntegerField()
    email = models.EmailField()
    phone_number = models.CharField(max_length=20)

If you query the database for a Person object, Django will retrieve the data and create a Python object representing the row in the database. This object is not serialized, as it is not in a format that can be easily transmitted over the network or stored in a file.

However, you can serialize the Person object using Django's built-in serialization framework. Here's an example:

from django.core import serializers

person = Person.objects.get(id=1)
data = serializers.serialize('json', [person])

This will create a JSON string that represents the Person object. However, the original Person object itself is not serialized, only its data is.