mirror of
https://github.com/django/django.git
synced 2024-12-24 10:05:46 +00:00
db94402ea6
git-svn-id: http://code.djangoproject.com/svn/django/trunk@1324 bcc190cf-cafb-0310-a4f2-bffc1f526a37
141 lines
4.8 KiB
Python
141 lines
4.8 KiB
Python
"""
|
|
7. The lookup API
|
|
|
|
This demonstrates features of the database API.
|
|
"""
|
|
|
|
from django.core import meta
|
|
|
|
class Article(meta.Model):
|
|
headline = meta.CharField(maxlength=100)
|
|
pub_date = meta.DateTimeField()
|
|
class META:
|
|
ordering = ('-pub_date', 'headline')
|
|
|
|
def __repr__(self):
|
|
return self.headline
|
|
|
|
API_TESTS = """
|
|
# Create a couple of Articles.
|
|
>>> from datetime import datetime
|
|
>>> a1 = articles.Article(headline='Article 1', pub_date=datetime(2005, 7, 26))
|
|
>>> a1.save()
|
|
>>> a2 = articles.Article(headline='Article 2', pub_date=datetime(2005, 7, 27))
|
|
>>> a2.save()
|
|
>>> a3 = articles.Article(headline='Article 3', pub_date=datetime(2005, 7, 27))
|
|
>>> a3.save()
|
|
>>> a4 = articles.Article(headline='Article 4', pub_date=datetime(2005, 7, 28))
|
|
>>> a4.save()
|
|
>>> a5 = articles.Article(headline='Article 5', pub_date=datetime(2005, 8, 1, 9, 0))
|
|
>>> a5.save()
|
|
>>> a6 = articles.Article(headline='Article 6', pub_date=datetime(2005, 8, 1, 8, 0))
|
|
>>> a6.save()
|
|
>>> a7 = articles.Article(headline='Article 7', pub_date=datetime(2005, 7, 27))
|
|
>>> a7.save()
|
|
|
|
# get_iterator() is just like get_list(), but it's a generator.
|
|
>>> for a in articles.get_iterator():
|
|
... print a.headline
|
|
Article 5
|
|
Article 6
|
|
Article 4
|
|
Article 2
|
|
Article 3
|
|
Article 7
|
|
Article 1
|
|
|
|
# get_iterator() takes the same lookup arguments as get_list().
|
|
>>> for a in articles.get_iterator(headline__endswith='4'):
|
|
... print a.headline
|
|
Article 4
|
|
|
|
# get_count() returns the number of objects matching search criteria.
|
|
>>> articles.get_count()
|
|
7L
|
|
>>> articles.get_count(pub_date__exact=datetime(2005, 7, 27))
|
|
3L
|
|
>>> articles.get_count(headline__startswith='Blah blah')
|
|
0L
|
|
|
|
# get_in_bulk() takes a list of IDs and returns a dictionary mapping IDs
|
|
# to objects.
|
|
>>> articles.get_in_bulk([1, 2])
|
|
{1: Article 1, 2: Article 2}
|
|
>>> articles.get_in_bulk([3])
|
|
{3: Article 3}
|
|
>>> articles.get_in_bulk([1000])
|
|
{}
|
|
|
|
# get_values() is just like get_list(), except it returns a list of
|
|
# dictionaries instead of object instances -- and you can specify which fields
|
|
# you want to retrieve.
|
|
>>> articles.get_values(fields=['headline'])
|
|
[{'headline': 'Article 5'}, {'headline': 'Article 6'}, {'headline': 'Article 4'}, {'headline': 'Article 2'}, {'headline': 'Article 3'}, {'headline': 'Article 7'}, {'headline': 'Article 1'}]
|
|
>>> articles.get_values(pub_date__exact=datetime(2005, 7, 27), fields=['id'])
|
|
[{'id': 2}, {'id': 3}, {'id': 7}]
|
|
>>> articles.get_values(fields=['id', 'headline']) == [{'id': 5, 'headline': 'Article 5'}, {'id': 6, 'headline': 'Article 6'}, {'id': 4, 'headline': 'Article 4'}, {'id': 2, 'headline': 'Article 2'}, {'id': 3, 'headline': 'Article 3'}, {'id': 7, 'headline': 'Article 7'}, {'id': 1, 'headline': 'Article 1'}]
|
|
True
|
|
|
|
# get_values_iterator() is just like get_values(), but it's a generator.
|
|
>>> for d in articles.get_values_iterator(fields=['id', 'headline']):
|
|
... i = d.items()
|
|
... i.sort()
|
|
... i
|
|
[('headline', 'Article 5'), ('id', 5)]
|
|
[('headline', 'Article 6'), ('id', 6)]
|
|
[('headline', 'Article 4'), ('id', 4)]
|
|
[('headline', 'Article 2'), ('id', 2)]
|
|
[('headline', 'Article 3'), ('id', 3)]
|
|
[('headline', 'Article 7'), ('id', 7)]
|
|
[('headline', 'Article 1'), ('id', 1)]
|
|
|
|
# Every DateField and DateTimeField creates get_next_by_FOO() and
|
|
# get_previous_by_FOO() methods.
|
|
# In the case of identical date values, these methods will use the ID as a
|
|
# fallback check. This guarantees that no records are skipped or duplicated.
|
|
>>> a1.get_next_by_pub_date()
|
|
Article 2
|
|
>>> a2.get_next_by_pub_date()
|
|
Article 3
|
|
>>> a3.get_next_by_pub_date()
|
|
Article 7
|
|
>>> a4.get_next_by_pub_date()
|
|
Article 6
|
|
>>> a5.get_next_by_pub_date()
|
|
Traceback (most recent call last):
|
|
...
|
|
ArticleDoesNotExist: Article does not exist for ...
|
|
>>> a6.get_next_by_pub_date()
|
|
Article 5
|
|
>>> a7.get_next_by_pub_date()
|
|
Article 4
|
|
|
|
>>> a7.get_previous_by_pub_date()
|
|
Article 3
|
|
>>> a6.get_previous_by_pub_date()
|
|
Article 4
|
|
>>> a5.get_previous_by_pub_date()
|
|
Article 6
|
|
>>> a4.get_previous_by_pub_date()
|
|
Article 7
|
|
>>> a3.get_previous_by_pub_date()
|
|
Article 2
|
|
>>> a2.get_previous_by_pub_date()
|
|
Article 1
|
|
|
|
# Underscores and percent signs have special meaning in the underlying
|
|
# database library, but Django handles the quoting of them automatically.
|
|
>>> a8 = articles.Article(headline='Article_ with underscore', pub_date=datetime(2005, 11, 20))
|
|
>>> a8.save()
|
|
>>> articles.get_list(headline__startswith='Article')
|
|
[Article_ with underscore, Article 5, Article 6, Article 4, Article 2, Article 3, Article 7, Article 1]
|
|
>>> articles.get_list(headline__startswith='Article_')
|
|
[Article_ with underscore]
|
|
>>> a9 = articles.Article(headline='Article% with percent sign', pub_date=datetime(2005, 11, 21))
|
|
>>> a9.save()
|
|
>>> articles.get_list(headline__startswith='Article')
|
|
[Article% with percent sign, Article_ with underscore, Article 5, Article 6, Article 4, Article 2, Article 3, Article 7, Article 1]
|
|
>>> articles.get_list(headline__startswith='Article%')
|
|
[Article% with percent sign]
|
|
"""
|