diff -r 261778de26ff -r 620f9b141567 thirdparty/google_appengine/lib/django/tests/modeltests/many_to_many/models.py --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/thirdparty/google_appengine/lib/django/tests/modeltests/many_to_many/models.py Tue Aug 26 21:49:54 2008 +0000 @@ -0,0 +1,258 @@ +""" +5. Many-to-many relationships + +To define a many-to-many relationship, use ManyToManyField(). + +In this example, an article can be published in multiple publications, +and a publication has multiple articles. +""" + +from django.db import models + +class Publication(models.Model): + title = models.CharField(maxlength=30) + + def __str__(self): + return self.title + + class Meta: + ordering = ('title',) + +class Article(models.Model): + headline = models.CharField(maxlength=100) + publications = models.ManyToManyField(Publication) + + def __str__(self): + return self.headline + + class Meta: + ordering = ('headline',) + +__test__ = {'API_TESTS':""" +# Create a couple of Publications. +>>> p1 = Publication(id=None, title='The Python Journal') +>>> p1.save() +>>> p2 = Publication(id=None, title='Science News') +>>> p2.save() +>>> p3 = Publication(id=None, title='Science Weekly') +>>> p3.save() + +# Create an Article. +>>> a1 = Article(id=None, headline='Django lets you build Web apps easily') +>>> a1.save() + +# Associate the Article with a Publication. +>>> a1.publications.add(p1) + +# Create another Article, and set it to appear in both Publications. +>>> a2 = Article(id=None, headline='NASA uses Python') +>>> a2.save() +>>> a2.publications.add(p1, p2) +>>> a2.publications.add(p3) + +# Adding a second time is OK +>>> a2.publications.add(p3) + +# Add a Publication directly via publications.add by using keyword arguments. +>>> new_publication = a2.publications.create(title='Highlights for Children') + +# Article objects have access to their related Publication objects. +>>> a1.publications.all() +[] +>>> a2.publications.all() +[, , , ] + +# Publication objects have access to their related Article objects. +>>> p2.article_set.all() +[] +>>> p1.article_set.all() +[, ] +>>> Publication.objects.get(id=4).article_set.all() +[] + +# We can perform kwarg queries across m2m relationships +>>> Article.objects.filter(publications__id__exact=1) +[, ] +>>> Article.objects.filter(publications__pk=1) +[, ] +>>> Article.objects.filter(publications=1) +[, ] +>>> Article.objects.filter(publications=p1) +[, ] + +>>> Article.objects.filter(publications__title__startswith="Science") +[, ] + +>>> Article.objects.filter(publications__title__startswith="Science").distinct() +[] + +# The count() function respects distinct() as well. +>>> Article.objects.filter(publications__title__startswith="Science").count() +2 + +>>> Article.objects.filter(publications__title__startswith="Science").distinct().count() +1 + +>>> Article.objects.filter(publications__in=[1,2]).distinct() +[, ] +>>> Article.objects.filter(publications__in=[1,p2]).distinct() +[, ] +>>> Article.objects.filter(publications__in=[p1,p2]).distinct() +[, ] + +# Reverse m2m queries are supported (i.e., starting at the table that doesn't +# have a ManyToManyField). +>>> Publication.objects.filter(id__exact=1) +[] +>>> Publication.objects.filter(pk=1) +[] + +>>> Publication.objects.filter(article__headline__startswith="NASA") +[, , , ] + +>>> Publication.objects.filter(article__id__exact=1) +[] +>>> Publication.objects.filter(article__pk=1) +[] +>>> Publication.objects.filter(article=1) +[] +>>> Publication.objects.filter(article=a1) +[] + +>>> Publication.objects.filter(article__in=[1,2]).distinct() +[, , , ] +>>> Publication.objects.filter(article__in=[1,a2]).distinct() +[, , , ] +>>> Publication.objects.filter(article__in=[a1,a2]).distinct() +[, , , ] + +# If we delete a Publication, its Articles won't be able to access it. +>>> p1.delete() +>>> Publication.objects.all() +[, , ] +>>> a1 = Article.objects.get(pk=1) +>>> a1.publications.all() +[] + +# If we delete an Article, its Publications won't be able to access it. +>>> a2.delete() +>>> Article.objects.all() +[] +>>> p2.article_set.all() +[] + +# Adding via the 'other' end of an m2m +>>> a4 = Article(headline='NASA finds intelligent life on Earth') +>>> a4.save() +>>> p2.article_set.add(a4) +>>> p2.article_set.all() +[] +>>> a4.publications.all() +[] + +# Adding via the other end using keywords +>>> new_article = p2.article_set.create(headline='Oxygen-free diet works wonders') +>>> p2.article_set.all() +[, ] +>>> a5 = p2.article_set.all()[1] +>>> a5.publications.all() +[] + +# Removing publication from an article: +>>> a4.publications.remove(p2) +>>> p2.article_set.all() +[] +>>> a4.publications.all() +[] + +# And from the other end +>>> p2.article_set.remove(a5) +>>> p2.article_set.all() +[] +>>> a5.publications.all() +[] + +# Relation sets can be assigned. Assignment clears any existing set members +>>> p2.article_set = [a4, a5] +>>> p2.article_set.all() +[, ] +>>> a4.publications.all() +[] +>>> a4.publications = [p3] +>>> p2.article_set.all() +[] +>>> a4.publications.all() +[] + +# Relation sets can be cleared: +>>> p2.article_set.clear() +>>> p2.article_set.all() +[] +>>> a4.publications.all() +[] + +# And you can clear from the other end +>>> p2.article_set.add(a4, a5) +>>> p2.article_set.all() +[, ] +>>> a4.publications.all() +[, ] +>>> a4.publications.clear() +>>> a4.publications.all() +[] +>>> p2.article_set.all() +[] + +# Relation sets can also be set using primary key values +>>> p2.article_set = [a4.id, a5.id] +>>> p2.article_set.all() +[, ] +>>> a4.publications.all() +[] +>>> a4.publications = [p3.id] +>>> p2.article_set.all() +[] +>>> a4.publications.all() +[] + +# Recreate the article and Publication we have deleted. +>>> p1 = Publication(id=None, title='The Python Journal') +>>> p1.save() +>>> a2 = Article(id=None, headline='NASA uses Python') +>>> a2.save() +>>> a2.publications.add(p1, p2, p3) + +# Bulk delete some Publications - references to deleted publications should go +>>> Publication.objects.filter(title__startswith='Science').delete() +>>> Publication.objects.all() +[, ] +>>> Article.objects.all() +[, , , ] +>>> a2.publications.all() +[] + +# Bulk delete some articles - references to deleted objects should go +>>> q = Article.objects.filter(headline__startswith='Django') +>>> print q +[] +>>> q.delete() + +# After the delete, the QuerySet cache needs to be cleared, and the referenced objects should be gone +>>> print q +[] +>>> p1.article_set.all() +[] + +# An alternate to calling clear() is to assign the empty set +>>> p1.article_set = [] +>>> p1.article_set.all() +[] + +>>> a2.publications = [p1, new_publication] +>>> a2.publications.all() +[, ] +>>> a2.publications = [] +>>> a2.publications.all() +[] + +"""}