"""

3. Giving models custom methods

Any method you add to a model will be available to instances.

"""

from django.db import models

import datetime

class Article(models.Model):

    headline = models.CharField(maxlength=100)

    pub_date = models.DateField()

    def __str__(self):

        return self.headline

    def was_published_today(self):

        return self.pub_date == datetime.date.today()

    def articles_from_same_day_1(self):

        return Article.objects.filter(pub_date=self.pub_date).exclude(id=self.id)

    def 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.

        """

        from django.db import connection

        cursor = connection.cursor()

        cursor.execute("""

            SELECT id, headline, pub_date

            FROM custom_methods_article

            WHERE pub_date = %s

                AND id != %s""", [str(self.pub_date), self.id])

        # The asterisk in "(*row)" tells Python to expand the list into

        # positional arguments to Article().

        return [self.__class__(*row) for row in cursor.fetchall()]

__test__ = {'API_TESTS':"""

# Create a couple of Articles.

>>> from datetime import date

>>> a = Article(id=None, headline='Area man programs in Python', pub_date=date(2005, 7, 27))

>>> a.save()

>>> b = Article(id=None, headline='Beatles reunite', pub_date=date(2005, 7, 27))

>>> b.save()

# Test the custom methods.

>>> a.was_published_today()

False

>>> a.articles_from_same_day_1()

[<Article: Beatles reunite>]

>>> a.articles_from_same_day_2()

[<Article: Beatles reunite>]

>>> b.articles_from_same_day_1()

[<Article: Area man programs in Python>]

>>> b.articles_from_same_day_2()

[<Article: Area man programs in Python>]

"""}