"""

35. DB-API Shortcuts

``get_object_or_404()`` is a shortcut function to be used in view functions for

performing a ``get()`` lookup and raising a ``Http404`` exception if a

``DoesNotExist`` exception was raised during the ``get()`` call.

``get_list_or_404()`` is a shortcut function to be used in view functions for

performing a ``filter()`` lookup and raising a ``Http404`` exception if a

``DoesNotExist`` exception was raised during the ``filter()`` call.

"""

from django.db import models

from django.http import Http404

from django.shortcuts import get_object_or_404, get_list_or_404

class Author(models.Model):

    name = models.CharField(max_length=50)

    def __unicode__(self):

        return self.name

class ArticleManager(models.Manager):

    def get_query_set(self):

        return super(ArticleManager, self).get_query_set().filter(authors__name__icontains='sir')

class Article(models.Model):

    authors = models.ManyToManyField(Author)

    title = models.CharField(max_length=50)

    objects = models.Manager()

    by_a_sir = ArticleManager()

    def __unicode__(self):

        return self.title