You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
107 lines
3.3 KiB
107 lines
3.3 KiB
""" |
|
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 |
|
|
|
__test__ = {'API_TESTS':""" |
|
# Create some Authors. |
|
>>> a = Author.objects.create(name="Brave Sir Robin") |
|
>>> a.save() |
|
>>> a2 = Author.objects.create(name="Patsy") |
|
>>> a2.save() |
|
|
|
# No Articles yet, so we should get a Http404 error. |
|
>>> get_object_or_404(Article, title="Foo") |
|
Traceback (most recent call last): |
|
... |
|
Http404: No Article matches the given query. |
|
|
|
# Create an Article. |
|
>>> article = Article.objects.create(title="Run away!") |
|
>>> article.authors = [a, a2] |
|
>>> article.save() |
|
|
|
# get_object_or_404 can be passed a Model to query. |
|
>>> get_object_or_404(Article, title__contains="Run") |
|
<Article: Run away!> |
|
|
|
# We can also use the the Article manager through an Author object. |
|
>>> get_object_or_404(a.article_set, title__contains="Run") |
|
<Article: Run away!> |
|
|
|
# No articles containing "Camelot". This should raise a Http404 error. |
|
>>> get_object_or_404(a.article_set, title__contains="Camelot") |
|
Traceback (most recent call last): |
|
... |
|
Http404: No Article matches the given query. |
|
|
|
# Custom managers can be used too. |
|
>>> get_object_or_404(Article.by_a_sir, title="Run away!") |
|
<Article: Run away!> |
|
|
|
# QuerySets can be used too. |
|
>>> get_object_or_404(Article.objects.all(), title__contains="Run") |
|
<Article: Run away!> |
|
|
|
# Just as when using a get() lookup, you will get an error if more than one |
|
# object is returned. |
|
>>> get_object_or_404(Author.objects.all()) |
|
Traceback (most recent call last): |
|
... |
|
MultipleObjectsReturned: get() returned more than one Author -- it returned ...! Lookup parameters were {} |
|
|
|
# Using an EmptyQuerySet raises a Http404 error. |
|
>>> get_object_or_404(Article.objects.none(), title__contains="Run") |
|
Traceback (most recent call last): |
|
... |
|
Http404: No Article matches the given query. |
|
|
|
# get_list_or_404 can be used to get lists of objects |
|
>>> get_list_or_404(a.article_set, title__icontains='Run') |
|
[<Article: Run away!>] |
|
|
|
# Http404 is returned if the list is empty. |
|
>>> get_list_or_404(a.article_set, title__icontains='Shrubbery') |
|
Traceback (most recent call last): |
|
... |
|
Http404: No Article matches the given query. |
|
|
|
# Custom managers can be used too. |
|
>>> get_list_or_404(Article.by_a_sir, title__icontains="Run") |
|
[<Article: Run away!>] |
|
|
|
# QuerySets can be used too. |
|
>>> get_list_or_404(Article.objects.all(), title__icontains="Run") |
|
[<Article: Run away!>] |
|
|
|
"""}
|
|
|