1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
"""
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 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!>]
"""}
|
