1 """ |
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2 3. Giving models custom methods |
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3 |
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4 Any method you add to a model will be available to instances. |
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5 """ |
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6 |
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7 from django.db import models |
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8 import datetime |
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9 |
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10 class Article(models.Model): |
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11 headline = models.CharField(maxlength=100) |
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12 pub_date = models.DateField() |
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13 |
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14 def __str__(self): |
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15 return self.headline |
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16 |
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17 def was_published_today(self): |
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18 return self.pub_date == datetime.date.today() |
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19 |
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20 def articles_from_same_day_1(self): |
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21 return Article.objects.filter(pub_date=self.pub_date).exclude(id=self.id) |
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22 |
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23 def articles_from_same_day_2(self): |
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24 """ |
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25 Verbose version of get_articles_from_same_day_1, which does a custom |
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26 database query for the sake of demonstration. |
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27 """ |
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28 from django.db import connection |
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29 cursor = connection.cursor() |
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30 cursor.execute(""" |
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31 SELECT id, headline, pub_date |
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32 FROM custom_methods_article |
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33 WHERE pub_date = %s |
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34 AND id != %s""", [str(self.pub_date), self.id]) |
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35 # The asterisk in "(*row)" tells Python to expand the list into |
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36 # positional arguments to Article(). |
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37 return [self.__class__(*row) for row in cursor.fetchall()] |
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38 |
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39 __test__ = {'API_TESTS':""" |
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40 # Create a couple of Articles. |
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41 >>> from datetime import date |
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42 >>> a = Article(id=None, headline='Area man programs in Python', pub_date=date(2005, 7, 27)) |
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43 >>> a.save() |
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44 >>> b = Article(id=None, headline='Beatles reunite', pub_date=date(2005, 7, 27)) |
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45 >>> b.save() |
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46 |
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47 # Test the custom methods. |
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48 >>> a.was_published_today() |
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49 False |
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50 >>> a.articles_from_same_day_1() |
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51 [<Article: Beatles reunite>] |
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52 >>> a.articles_from_same_day_2() |
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53 [<Article: Beatles reunite>] |
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54 >>> b.articles_from_same_day_1() |
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55 [<Article: Area man programs in Python>] |
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56 >>> b.articles_from_same_day_2() |
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57 [<Article: Area man programs in Python>] |
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58 """} |
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