Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Browse files

magic-removal: Fixed #1143 -- Fixed backwards incompatibilities in ma…

…ny-to-many DB API lookups, added support for reverse many-to-many lookups, added unit tests. Thanks, Russ

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@1802 bcc190cf-cafb-0310-a4f2-bffc1f526a37
  • Loading branch information...
commit b72373a7fdb45d26f2833b33f33329390039ba28 1 parent 9d5272d
@adrianholovaty adrianholovaty authored
View
45 django/db/models/query.py
@@ -236,10 +236,11 @@ def parse_lookup(kwarg_items, opts):
# is set to True, which means the kwarg was bad.
# Example: choices.get_list(poll__exact='foo')
throw_bad_kwarg_error(kwarg)
- # Try many-to-many relationships first...
+ # Try many-to-many relationships in the direction in which they are
+ # originally defined (i.e., the class that defines the ManyToManyField)
for f in current_opts.many_to_many:
if f.name == current:
- rel_table_alias = backend.quote_name(current_table_alias + LOOKUP_SEPARATOR + current)
+ rel_table_alias = backend.quote_name("m2m_" + current_table_alias + LOOKUP_SEPARATOR + current)
joins[rel_table_alias] = (
backend.quote_name(f.get_m2m_db_table(current_opts)),
@@ -275,6 +276,46 @@ def parse_lookup(kwarg_items, opts):
param_required = True
current_opts = f.rel.to._meta
raise StopIteration
+ # Try many-to-many relationships first in the reverse direction
+ # (i.e., from the class does not have the ManyToManyField)
+ for f in current_opts.get_all_related_many_to_many_objects():
+ if f.name == current:
+ rel_table_alias = backend.quote_name("m2m_" + current_table_alias + LOOKUP_SEPARATOR + current)
+
+ joins[rel_table_alias] = (
+ backend.quote_name(f.field.get_m2m_db_table(f.opts)),
+ "INNER JOIN",
+ '%s.%s = %s.%s' %
+ (backend.quote_name(current_table_alias),
+ backend.quote_name(current_opts.pk.column),
+ rel_table_alias,
+ backend.quote_name(current_opts.object_name.lower() + '_id'))
+ )
+
+ # Optimization: In the case of primary-key lookups, we
+ # don't have to do an extra join.
+ if lookup_list and lookup_list[0] == f.opts.pk.name and lookup_type == 'exact':
+ where.append(get_where_clause(lookup_type, rel_table_alias+'.',
+ f.opts.object_name.lower()+'_id', kwarg_value))
+ params.extend(f.field.get_db_prep_lookup(lookup_type, kwarg_value))
+ lookup_list.pop()
+ param_required = False
+ else:
+ new_table_alias = current_table_alias + LOOKUP_SEPARATOR + current
+
+ joins[backend.quote_name(new_table_alias)] = (
+ backend.quote_name(f.opts.db_table),
+ "INNER JOIN",
+ '%s.%s = %s.%s' %
+ (rel_table_alias,
+ backend.quote_name(f.opts.object_name.lower() + '_id'),
+ backend.quote_name(new_table_alias),
+ backend.quote_name(f.opts.pk.column))
+ )
+ current_table_alias = new_table_alias
+ param_required = True
+ current_opts = f.opts
+ raise StopIteration
for f in current_opts.fields:
# Try many-to-one relationships...
if f.rel and f.name == current:
View
25 tests/modeltests/many_to_many/models.py
@@ -28,6 +28,8 @@ def __repr__(self):
>>> p1.save()
>>> p2 = Publication(id=None, title='Science News')
>>> p2.save()
+>>> p3 = Publication(id=None, title='Science Weekly')
+>>> p3.save()
# Create an Article.
>>> a1 = Article(id=None, headline='Django lets you build Web apps easily')
@@ -50,14 +52,14 @@ def __repr__(self):
True
>>> a2.set_publications([p1.id])
True
->>> a2.set_publications([p1.id, p2.id])
+>>> a2.set_publications([p1.id, p2.id, p3.id])
True
# Article objects have access to their related Publication objects.
>>> a1.get_publication_list()
[The Python Journal]
>>> a2.get_publication_list()
-[The Python Journal, Science News]
+[The Python Journal, Science News, Science Weekly]
# Publication objects have access to their related Article objects.
>>> p2.get_article_list()
@@ -65,10 +67,27 @@ def __repr__(self):
>>> p1.get_article_list(order_by=['headline'])
[Django lets you build Web apps easily, NASA uses Python]
+# We can perform kwarg queries across m2m relationships
+>>> Article.objects.get_list(publications__pk=1)
+[Django lets you build Web apps easily, NASA uses Python]
+
+>>> Article.objects.get_list(publications__title__startswith="Science")
+[NASA uses Python, NASA uses Python]
+
+>>> Article.objects.get_list(publications__title__startswith="Science", distinct=True)
+[NASA uses Python]
+
+# Reverse m2m queries (i.e., start at the table that doesn't have a ManyToManyField)
+>>> Publication.objects.get_list(articles__headline__startswith="NASA")
+[The Python Journal, Science News, Science Weekly]
+
+>>> Publication.objects.get_list(articles__pk=1)
+[The Python Journal]
+
# If we delete a Publication, its Articles won't be able to access it.
>>> p1.delete()
>>> Publication.objects.get_list()
-[Science News]
+[Science News, Science Weekly]
>>> a1 = Article.objects.get_object(pk=1)
>>> a1.get_publication_list()
[]
View
2  tests/modeltests/one_to_one/models.py
@@ -66,6 +66,8 @@ def __repr__(self):
>>> Restaurant.objects.get_object(place__id__exact=1)
Demon Dogs the restaurant
+>>> Restaurant.objects.get_object(place__name__startswith="Demon")
+Demon Dogs the restaurant
>>> Restaurant.objects.get_object(pk=1)
Demon Dogs the restaurant
Please sign in to comment.
Something went wrong with that request. Please try again.