mirror of
https://github.com/django/django.git
synced 2024-12-25 10:35:48 +00:00
25264c8604
git-svn-id: http://code.djangoproject.com/svn/django/trunk@549 bcc190cf-cafb-0310-a4f2-bffc1f526a37
73 lines
2.4 KiB
Python
73 lines
2.4 KiB
Python
"""
|
|
3. Giving models custom methods and custom module-level functions
|
|
|
|
Any method you add to a model will be available to instances.
|
|
|
|
Custom methods have the same namespace as if the model class were defined
|
|
in the dynamically-generated module. That is, methods can access
|
|
``get_list()``, ``get_object()``, ``AddManipulator``, and all other
|
|
module-level objects.
|
|
|
|
Also, custom methods have access to a few commonly-used objects for
|
|
convenience:
|
|
|
|
* The ``datetime`` module from Python's standard library.
|
|
* The ``db`` object from ``django.core.db``. This represents the database
|
|
connection, so you can do custom queries via a cursor object.
|
|
|
|
If your model method starts with "_module_", it'll be a module-level function
|
|
instead of a method. Otherwise, custom module-level functions have the same
|
|
namespace as custom methods.
|
|
"""
|
|
|
|
from django.core import meta
|
|
|
|
class Article(meta.Model):
|
|
headline = meta.CharField(maxlength=100)
|
|
pub_date = meta.DateField()
|
|
|
|
def __repr__(self):
|
|
return self.headline
|
|
|
|
def was_published_today(self):
|
|
return self.pub_date == datetime.date.today()
|
|
|
|
def get_articles_from_same_day_1(self):
|
|
return get_list(id__ne=self.id, pub_date__exact=self.pub_date)
|
|
|
|
def get_articles_from_same_day_2(self):
|
|
"""
|
|
Verbose version of get_articles_from_same_day_1, which does a custom
|
|
database query for the sake of demonstration.
|
|
"""
|
|
cursor = db.cursor()
|
|
cursor.execute("""
|
|
SELECT id, headline, pub_date
|
|
FROM custom_methods_articles
|
|
WHERE pub_date = %s
|
|
AND id != %s""", [str(self.pub_date), self.id])
|
|
# The asterisk in "Article(*row)" tells Python to expand the list into
|
|
# positional arguments to Article().
|
|
return [Article(*row) for row in cursor.fetchall()]
|
|
|
|
API_TESTS = """
|
|
# Create a couple of Articles.
|
|
>>> from datetime import date
|
|
>>> a = articles.Article(id=None, headline='Area man programs in Python', pub_date=date(2005, 7, 27))
|
|
>>> a.save()
|
|
>>> b = articles.Article(id=None, headline='Beatles reunite', pub_date=date(2005, 7, 27))
|
|
>>> b.save()
|
|
|
|
# Test the custom methods.
|
|
>>> a.was_published_today()
|
|
False
|
|
>>> a.get_articles_from_same_day_1()
|
|
[Beatles reunite]
|
|
>>> a.get_articles_from_same_day_2()
|
|
[Beatles reunite]
|
|
>>> b.get_articles_from_same_day_1()
|
|
[Area man programs in Python]
|
|
>>> b.get_articles_from_same_day_2()
|
|
[Area man programs in Python]
|
|
"""
|