tests/modeltests/or_lookups/models.py

   1 """
   2 19. OR lookups
   3
   4 To perform an OR lookup, or a lookup that combines ANDs and ORs,
   5 combine QuerySet objects using & and | operators.
   6
   7 Alternatively, use positional arguments, and pass one or more expressions of
   8 clauses using the variable ``django.db.models.Q`` (or any object with an
   9 add_to_query method).
  10 """
  11
  12 from django.db import models
  13
  14 class Article(models.Model):
  15     headline = models.CharField(max_length=50)
  16     pub_date = models.DateTimeField()
  17
  18     class Meta:
  19        ordering = ('pub_date',)
  20
  21     def __unicode__(self):
  22         return self.headline
  23
  24 __test__ = {'API_TESTS':"""
  25 >>> from datetime import datetime
  26 >>> from django.db.models import Q
  27
  28 >>> a1 = Article(headline='Hello', pub_date=datetime(2005, 11, 27))
  29 >>> a1.save()
  30
  31 >>> a2 = Article(headline='Goodbye', pub_date=datetime(2005, 11, 28))
  32 >>> a2.save()
  33
  34 >>> a3 = Article(headline='Hello and goodbye', pub_date=datetime(2005, 11, 29))
  35 >>> a3.save()
  36
  37 >>> Article.objects.filter(headline__startswith='Hello') |  Article.objects.filter(headline__startswith='Goodbye')
  38 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  39
  40 >>> Article.objects.filter(Q(headline__startswith='Hello') | Q(headline__startswith='Goodbye'))
  41 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  42
  43 >>> Article.objects.filter(Q(headline__startswith='Hello') & Q(headline__startswith='Goodbye'))
  44 []
  45
  46 # You can shorten this syntax with code like the following,
  47 # which is especially useful if building the query in stages:
  48 >>> articles = Article.objects.all()
  49 >>> articles.filter(headline__startswith='Hello') & articles.filter(headline__startswith='Goodbye')
  50 []
  51
  52 >>> articles.filter(headline__startswith='Hello') & articles.filter(headline__contains='bye')
  53 [<Article: Hello and goodbye>]
  54
  55 >>> Article.objects.filter(Q(headline__contains='bye'), headline__startswith='Hello')
  56 [<Article: Hello and goodbye>]
  57
  58 >>> Article.objects.filter(headline__contains='Hello') | Article.objects.filter(headline__contains='bye')
  59 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  60
  61 >>> Article.objects.filter(headline__iexact='Hello') | Article.objects.filter(headline__contains='ood')
  62 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  63
  64 >>> Article.objects.filter(Q(pk=1) | Q(pk=2))
  65 [<Article: Hello>, <Article: Goodbye>]
  66
  67 >>> Article.objects.filter(Q(pk=1) | Q(pk=2) | Q(pk=3))
  68 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  69
  70 # You could also use "in" to accomplish the same as above.
  71 >>> Article.objects.filter(pk__in=[1,2,3])
  72 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  73 >>> Article.objects.filter(pk__in=(1,2,3))
  74 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  75
  76 >>> Article.objects.filter(pk__in=[1,2,3,4])
  77 [<Article: Hello>, <Article: Goodbye>, <Article: Hello and goodbye>]
  78
  79 # Passing "in" an empty list returns no results ...
  80 >>> Article.objects.filter(pk__in=[])
  81 []
  82
  83 # ... but can return results if we OR it with another query.
  84 >>> Article.objects.filter(Q(pk__in=[]) | Q(headline__icontains='goodbye'))
  85 [<Article: Goodbye>, <Article: Hello and goodbye>]
  86
  87 # Q arg objects are ANDed
  88 >>> Article.objects.filter(Q(headline__startswith='Hello'), Q(headline__contains='bye'))
  89 [<Article: Hello and goodbye>]
  90
  91 # Q arg AND order is irrelevant
  92 >>> Article.objects.filter(Q(headline__contains='bye'), headline__startswith='Hello')
  93 [<Article: Hello and goodbye>]
  94
  95 # Q objects can be negated
  96 >>> Article.objects.filter(Q(pk=1) | ~Q(pk=2))
  97 [<Article: Hello>, <Article: Hello and goodbye>]
  98 >>> Article.objects.filter(~Q(pk=1) & ~Q(pk=2))
  99 [<Article: Hello and goodbye>]
 100
 101 # This allows for more complex queries than filter() and exclude() alone would
 102 # allow
 103 >>> Article.objects.filter(Q(pk=1) & (~Q(pk=2) | Q(pk=3)))
 104 [<Article: Hello>]
 105
 106 # Try some arg queries with operations other than filter.
 107 >>> Article.objects.get(Q(headline__startswith='Hello'), Q(headline__contains='bye'))
 108 <Article: Hello and goodbye>
 109
 110 >>> Article.objects.filter(Q(headline__startswith='Hello') | Q(headline__contains='bye')).count()
 111 3
 112
 113 >>> list(Article.objects.filter(Q(headline__startswith='Hello'), Q(headline__contains='bye')).values())
 114 [{'headline': u'Hello and goodbye', 'pub_date': datetime.datetime(2005, 11, 29, 0, 0), 'id': 3}]
 115
 116 >>> Article.objects.filter(Q(headline__startswith='Hello')).in_bulk([1,2])
 117 {1: <Article: Hello>}
 118
 119 # Demonstrating exclude with a Q object
 120 >>> Article.objects.exclude(Q(headline__startswith='Hello'))
 121 [<Article: Goodbye>]
 122
 123 # The 'complex_filter' method supports framework features such as
 124 # 'limit_choices_to' which normally take a single dictionary of lookup arguments
 125 # but need to support arbitrary queries via Q objects too.
 126 >>> Article.objects.complex_filter({'pk': 1})
 127 [<Article: Hello>]
 128 >>> Article.objects.complex_filter(Q(pk=1) | Q(pk=2))
 129 [<Article: Hello>, <Article: Goodbye>]
 130 """}