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b3b71a0922
loading/saving interactions with the databases into django.db.backend. This helps external db backend writers and removes a bunch of database-specific if-tests in django.db.models.fields. Great work from Leo Soto. git-svn-id: http://code.djangoproject.com/svn/django/trunk@8131 bcc190cf-cafb-0310-a4f2-bffc1f526a37
60 lines
1.8 KiB
Python
60 lines
1.8 KiB
Python
"""
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3. Giving models custom methods
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Any method you add to a model will be available to instances.
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"""
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from django.db import models
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import datetime
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class Article(models.Model):
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headline = models.CharField(max_length=100)
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pub_date = models.DateField()
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def __unicode__(self):
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return self.headline
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def was_published_today(self):
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return self.pub_date == datetime.date.today()
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def articles_from_same_day_1(self):
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return Article.objects.filter(pub_date=self.pub_date).exclude(id=self.id)
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def articles_from_same_day_2(self):
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"""
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Verbose version of get_articles_from_same_day_1, which does a custom
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database query for the sake of demonstration.
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"""
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from django.db import connection
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cursor = connection.cursor()
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cursor.execute("""
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SELECT id, headline, pub_date
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FROM custom_methods_article
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WHERE pub_date = %s
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AND id != %s""", [connection.ops.value_to_db_date(self.pub_date),
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self.id])
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# The asterisk in "(*row)" tells Python to expand the list into
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# positional arguments to Article().
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return [self.__class__(*row) for row in cursor.fetchall()]
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__test__ = {'API_TESTS':"""
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# Create a couple of Articles.
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>>> from datetime import date
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>>> a = Article(id=None, headline='Area man programs in Python', pub_date=date(2005, 7, 27))
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>>> a.save()
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>>> b = Article(id=None, headline='Beatles reunite', pub_date=date(2005, 7, 27))
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>>> b.save()
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# Test the custom methods.
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>>> a.was_published_today()
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False
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>>> a.articles_from_same_day_1()
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[<Article: Beatles reunite>]
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>>> a.articles_from_same_day_2()
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[<Article: Beatles reunite>]
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>>> b.articles_from_same_day_1()
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[<Article: Area man programs in Python>]
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>>> b.articles_from_same_day_2()
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[<Article: Area man programs in Python>]
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"""}
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