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Code Issues 32 Releases Wiki Activity

Allowed custom querysets when prefetching single valued relations

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The original patch for custom prefetches didn't allow usage of custom
queryset for single valued relations (along ForeignKey or OneToOneKey).
Allowing these enables calling performance oriented queryset methods like
select_related or defer/only.

Thanks @akaariai and @timgraham for the reviews. Refs #17001.
This commit is contained in:
Loic Bistuer
2014-01-17 01:24:39 +07:00
committed by Anssi Kääriäinen
parent c8d61fa109
commit 7bbb6958dc
5 changed files with 112 additions and 23 deletions
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13
django/db/models/query.py
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@@ -1667,8 +1667,8 @@ class Prefetch(object):
def get_current_to_attr(self, level):
parts = self.prefetch_to.split(LOOKUP_SEP)
to_attr = parts[level]
to_list = self.to_attr and level == len(parts) - 1
return to_attr, to_list
as_attr = self.to_attr and level == len(parts) - 1
return to_attr, as_attr
def get_current_queryset(self, level):
if self.get_current_prefetch_to(level) == self.prefetch_to:
@@ -1913,12 +1913,13 @@ def prefetch_one_level(instances, prefetcher, lookup, level):
for obj in instances:
instance_attr_val = instance_attr(obj)
vals = rel_obj_cache.get(instance_attr_val, [])
to_attr, as_attr = lookup.get_current_to_attr(level)
if single:
# Need to assign to single cache on instance
setattr(obj, cache_name, vals[0] if vals else None)
val = vals[0] if vals else None
to_attr = to_attr if as_attr else cache_name
setattr(obj, to_attr, val)
else:
to_attr, to_list = lookup.get_current_to_attr(level)
if to_list:
if as_attr:
setattr(obj, to_attr, vals)
else:
# Cache in the QuerySet.all().