p15693087
/
django
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

magic-removal: Implemented SingleRelatedObjectDescriptor -- descriptor lookup for many-to-one related lookup, e.g. choice.poll. Old syntax, choice.get_poll(), still works for the moment. 

git-svn-id: http://code.djangoproject.com/svn/django/branches/magic-removal@2148 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Adrian Holovaty 2006-01-28 19:27:51 +00:00
parent b266091a2a
commit 7e0ba90442
1 changed files with 28 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
django/db/models/fields/related.py
View File

@ -68,7 +68,28 @@ class SingleRelatedObjectDescriptor(object):
# a single "remote" value. # a single "remote" value.
# In the example "choice.poll", the poll attribute is a # In the example "choice.poll", the poll attribute is a
# SingleRelatedObjectDescriptor instance. # SingleRelatedObjectDescriptor instance.
pass # Not yet implemented def __init__(self, field_with_rel):
self.field = field_with_rel
def __get__(self, instance, instance_type=None):
if instance is None:
raise AttributeError, "%s must be accessed via instance" % self.field.name
else:
cache_name = self.field.get_cache_name()
try:
return getattr(instance, cache_name)
except AttributeError:
val = getattr(instance, self.field.attname)
if val is None:
raise self.field.rel.to.DoesNotExist
other_field = self.field.rel.get_related_field()
if other_field.rel:
params = {'%s__%s__exact' % (self.field.rel.field_name, other_field.rel.field_name): val}
else:
params = {'%s__exact' % self.field.rel.field_name: val}
rel_obj = self.field.rel.to._default_manager.get_object(**params)
setattr(instance, cache_name, rel_obj)
return rel_obj
class ManyRelatedObjectsDescriptor(object): class ManyRelatedObjectsDescriptor(object):
# This class provides the functionality that makes the related-object # This class provides the functionality that makes the related-object
@ -192,6 +213,12 @@ class ForeignKey(RelatedField, Field):
def contribute_to_class(self, cls, name): def contribute_to_class(self, cls, name):
super(ForeignKey, self).contribute_to_class(cls, name) super(ForeignKey, self).contribute_to_class(cls, name)
setattr(cls, self.name, SingleRelatedObjectDescriptor(self))
# TODO: Delete the rest of this function
# to remove support for old-style related lookup.
# Add methods for many-to-one related objects. # Add methods for many-to-one related objects.
# EXAMPLES: Choice.get_poll(), Story.get_dateline() # EXAMPLES: Choice.get_poll(), Story.get_dateline()
setattr(cls, 'get_%s' % self.name, curry(cls._get_foreign_key_object, field_with_rel=self)) setattr(cls, 'get_%s' % self.name, curry(cls._get_foreign_key_object, field_with_rel=self))