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Code Issues 32 Releases Wiki Activity

queryset-refactor: Added caching for reverse-one-to-one lookups.

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This is the only type of reverse lookup where caching makes sense might make
some kinds of model inheritance interactions more database friendly.


git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@7171 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick 2008-02-28 13:21:33 +00:00
parent 33a0862215
commit a9008f8928
1 changed files with 8 additions and 3 deletions
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11
django/db/models/fields/related.py
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@ -125,14 +125,19 @@ class SingleRelatedObjectDescriptor(object):
# SingleRelatedObjectDescriptor instance. # SingleRelatedObjectDescriptor instance.
def __init__(self, related): def __init__(self, related):
self.related = related self.related = related
self.cache_name = '_%s_cache' % related.field.name
def __get__(self, instance, instance_type=None): def __get__(self, instance, instance_type=None):
if instance is None: if instance is None:
raise AttributeError, "%s must be accessed via instance" % self.related.opts.object_name raise AttributeError, "%s must be accessed via instance" % self.related.opts.object_name
params = {'%s__pk' % self.related.field.name: instance._get_pk_val()} try:
rel_obj = self.related.model._default_manager.get(**params) return getattr(instance, self.cache_name)
return rel_obj except AttributeError:
params = {'%s__pk' % self.related.field.name: instance._get_pk_val()}
rel_obj = self.related.model._default_manager.get(**params)
setattr(instance, self.cache_name, rel_obj)
return rel_obj
def __set__(self, instance, value): def __set__(self, instance, value):
if instance is None: if instance is None: