Can you explain what the proxy pattern is in the context of Django and how it is used?

In the context of Django, the proxy pattern (proxy model) is a way to create a new model that uses the same database table as an existing model but with different behavior at the Python level (for example, with a different manager, methods, or metadata).

A proxy model does not create a new table in the database but allows extending or changing the behavior of the model without altering the data structure.

Example of using a proxy model:

from django.db import models

class Person(models.Model):
    name = models.CharField(max_length=100)
    age = models.IntegerField()

class PersonProxy(Person):
    class Meta:
        proxy = True
        ordering = ['age']

    def is_adult(self):
        return self.age >= 18

Here, PersonProxy uses the same table as Person but adds the is_adult method and changes the ordering. This is useful when you want to add behavior without changing the database.