by specifying the proxy meta attribute model subclasses can specify that they will take data directly from the table of their base class table rather than using a new table of their own this allows them to act as simple proxies providing a modified interface to the data from the base class a couple of managers for testing managing overriding in proxy model cases a simple concrete base class a simple abstract base class to be used for error checking a proxy subclass this should not get a new table overrides the default manager a class with the default manager from person plus a secondary manager a nonproxy subclass of a proxy it should get a new table we can even have proxies of proxies and subclass of those we can still use selectrelated to include related models in our querysets proxy models still works with filters on related fields and selectrelated even when mixed with model inheritance proxy of an inherited class a proxy of proxy model with related field a model that has relation to a proxy model or to a proxy of proxy model a couple of managers for testing managing overriding in proxy model cases a simple concrete base class a simple abstract base class to be used for error checking a proxy subclass this should not get a new table overrides the default manager a class with the default manager from person plus a secondary manager a non proxy subclass of a proxy it should get a new table we can even have proxies of proxies and subclass of those we can still use select_related to include related models in our querysets proxy models still works with filters on related fields and select_related even when mixed with model inheritance proxy of an inherited class a proxy of proxy model with related field a model that has relation to a proxy model or to a proxy of proxy model
from django.db import models




class PersonManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().exclude(name="fred")


class SubManager(models.Manager):
    def get_queryset(self):
        return super().get_queryset().exclude(name="wilma")


class Person(models.Model):
    

    name = models.CharField(max_length=50)

    objects = PersonManager()

    def __str__(self):
        return self.name


class Abstract(models.Model):
    

    data = models.CharField(max_length=10)

    class Meta:
        abstract = True


class MyPerson(Person):
    

    class Meta:
        proxy = True
        ordering = ["name"]
        permissions = (("display_users", "May display users information"),)

    objects = SubManager()
    other = PersonManager()

    def has_special_name(self):
        return self.name.lower() == "special"


class ManagerMixin(models.Model):
    excluder = SubManager()

    class Meta:
        abstract = True


class OtherPerson(Person, ManagerMixin):
    

    class Meta:
        proxy = True
        ordering = ["name"]


class StatusPerson(MyPerson):
    

    status = models.CharField(max_length=80)

    objects = models.Manager()





class MyPersonProxy(MyPerson):
    class Meta:
        proxy = True


class LowerStatusPerson(MyPersonProxy):
    status = models.CharField(max_length=80)

    objects = models.Manager()


class User(models.Model):
    name = models.CharField(max_length=100)

    def __str__(self):
        return self.name


class UserProxy(User):
    class Meta:
        proxy = True


class AnotherUserProxy(User):
    class Meta:
        proxy = True


class UserProxyProxy(UserProxy):
    class Meta:
        proxy = True


class MultiUserProxy(UserProxy, AnotherUserProxy):
    class Meta:
        proxy = True





class Country(models.Model):
    name = models.CharField(max_length=50)


class State(models.Model):
    name = models.CharField(max_length=50)
    country = models.ForeignKey(Country, models.CASCADE)

    def __str__(self):
        return self.name


class StateProxy(State):
    class Meta:
        proxy = True






class BaseUser(models.Model):
    name = models.CharField(max_length=255)

    def __str__(self):
        return ":".join(
            (
                self.__class__.__name__,
                self.name,
            )
        )


class TrackerUser(BaseUser):
    status = models.CharField(max_length=50)


class ProxyTrackerUser(TrackerUser):
    class Meta:
        proxy = True


class Issue(models.Model):
    summary = models.CharField(max_length=255)
    assignee = models.ForeignKey(
        ProxyTrackerUser, models.CASCADE, related_name="issues"
    )

    def __str__(self):
        return ":".join(
            (
                self.__class__.__name__,
                self.summary,
            )
        )


class Bug(Issue):
    version = models.CharField(max_length=50)
    reporter = models.ForeignKey(BaseUser, models.CASCADE)


class ProxyBug(Bug):
    

    class Meta:
        proxy = True


class ProxyProxyBug(ProxyBug):
    

    class Meta:
        proxy = True


class Improvement(Issue):
    

    version = models.CharField(max_length=50)
    reporter = models.ForeignKey(ProxyTrackerUser, models.CASCADE)
    associated_bug = models.ForeignKey(ProxyProxyBug, models.CASCADE)


class ProxyImprovement(Improvement):
    class Meta:
        proxy = True