--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parts/django/tests/modeltests/model_inheritance/models.py	Sat Jan 08 11:20:57 2011 +0530
@@ -0,0 +1,145 @@
+"""
+XX. Model inheritance
+
+Model inheritance exists in two varieties:
+    - abstract base classes which are a way of specifying common
+      information inherited by the subclasses. They don't exist as a separate
+      model.
+    - non-abstract base classes (the default), which are models in their own
+      right with their own database tables and everything. Their subclasses
+      have references back to them, created automatically.
+
+Both styles are demonstrated here.
+"""
+
+from django.db import models
+
+#
+# Abstract base classes
+#
+
+class CommonInfo(models.Model):
+    name = models.CharField(max_length=50)
+    age = models.PositiveIntegerField()
+
+    class Meta:
+        abstract = True
+        ordering = ['name']
+
+    def __unicode__(self):
+        return u'%s %s' % (self.__class__.__name__, self.name)
+
+class Worker(CommonInfo):
+    job = models.CharField(max_length=50)
+
+class Student(CommonInfo):
+    school_class = models.CharField(max_length=10)
+
+    class Meta:
+        pass
+
+class StudentWorker(Student, Worker):
+    pass
+
+#
+# Abstract base classes with related models
+#
+
+class Post(models.Model):
+    title = models.CharField(max_length=50)
+
+class Attachment(models.Model):
+    post = models.ForeignKey(Post, related_name='attached_%(class)s_set')
+    content = models.TextField()
+
+    class Meta:
+        abstract = True
+
+    def __unicode__(self):
+        return self.content
+
+class Comment(Attachment):
+    is_spam = models.BooleanField()
+
+class Link(Attachment):
+    url = models.URLField()
+
+#
+# Multi-table inheritance
+#
+
+class Chef(models.Model):
+    name = models.CharField(max_length=50)
+
+    def __unicode__(self):
+        return u"%s the chef" % self.name
+
+class Place(models.Model):
+    name = models.CharField(max_length=50)
+    address = models.CharField(max_length=80)
+
+    def __unicode__(self):
+        return u"%s the place" % self.name
+
+class Rating(models.Model):
+    rating = models.IntegerField(null=True, blank=True)
+
+    class Meta:
+        abstract = True
+        ordering = ['-rating']
+
+class Restaurant(Place, Rating):
+    serves_hot_dogs = models.BooleanField()
+    serves_pizza = models.BooleanField()
+    chef = models.ForeignKey(Chef, null=True, blank=True)
+
+    class Meta(Rating.Meta):
+        db_table = 'my_restaurant'
+
+    def __unicode__(self):
+        return u"%s the restaurant" % self.name
+
+class ItalianRestaurant(Restaurant):
+    serves_gnocchi = models.BooleanField()
+
+    def __unicode__(self):
+        return u"%s the italian restaurant" % self.name
+
+class Supplier(Place):
+    customers = models.ManyToManyField(Restaurant, related_name='provider')
+
+    def __unicode__(self):
+        return u"%s the supplier" % self.name
+
+class ParkingLot(Place):
+    # An explicit link to the parent (we can control the attribute name).
+    parent = models.OneToOneField(Place, primary_key=True, parent_link=True)
+    main_site = models.ForeignKey(Place, related_name='lot')
+
+    def __unicode__(self):
+        return u"%s the parking lot" % self.name
+
+#
+# Abstract base classes with related models where the sub-class has the
+# same name in a different app and inherits from the same abstract base
+# class.
+# NOTE: The actual API tests for the following classes are in
+#       model_inheritance_same_model_name/models.py - They are defined
+#       here in order to have the name conflict between apps
+#
+
+class Title(models.Model):
+    title = models.CharField(max_length=50)
+
+class NamedURL(models.Model):
+    title = models.ForeignKey(Title, related_name='attached_%(app_label)s_%(class)s_set')
+    url = models.URLField()
+
+    class Meta:
+        abstract = True
+
+class Copy(NamedURL):
+    content = models.TextField()
+
+    def __unicode__(self):
+        return self.content