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Fixed #19964 -- Removed relabel_aliases from some structs

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Before there was need to have both .relabel_aliases() and .clone() for
many structs. Now there is only relabeled_clone() for those structs
where alias is the only mutable attribute.
This commit is contained in:
Anssi Kääriäinen 2013-03-02 01:06:56 +02:00
parent 679af4058d
commit d744c550d5
9 changed files with 79 additions and 105 deletions
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31
django/db/models/sql/query.py
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@ -294,8 +294,7 @@ class Query(object):
obj.select_for_update_nowait = self.select_for_update_nowait
obj.select_related = self.select_related
obj.related_select_cols = []
obj.aggregates = SortedDict((k, v.clone())
for k, v in self.aggregates.items())
obj.aggregates = self.aggregates.copy()
if self.aggregate_select_mask is None:
obj.aggregate_select_mask = None
else:
@ -559,9 +558,8 @@ class Query(object):
new_col = change_map.get(col[0], col[0]), col[1]
self.select.append(SelectInfo(new_col, field))
else:
item = col.clone()
item.relabel_aliases(change_map)
self.select.append(SelectInfo(item, field))
new_col = col.relabeled_clone(change_map)
self.select.append(SelectInfo(new_col, field))
if connector == OR:
# It would be nice to be able to handle this, but the queries don't
@ -769,26 +767,6 @@ class Query(object):
The principle for promotion is: any alias which is used (it is in
alias_usage_counts), is not used by every child of the ORed filter,
and isn't pre-existing needs to be promoted to LOUTER join.
Some examples (assume all joins used are nullable):
- existing filter: a__f1=foo
- add filter: b__f1=foo|b__f2=foo
In this case we should not promote either of the joins (using INNER
doesn't remove results). We correctly avoid join promotion, because
a is not used in this branch, and b is used two times.
- add filter a__f1=foo|b__f2=foo
In this case we should promote both a and b, otherwise they will
remove results. We will also correctly do that as both aliases are
used, and in addition both are used only once while there are two
filters.
- existing: a__f1=bar
- add filter: a__f2=foo|b__f2=foo
We will not promote a as it is previously used. If the join results
in null, the existing filter can't succeed.
The above (and some more) are tested in queries.DisjunctionPromotionTests
"""
for alias, use_count in alias_usage_counts.items():
if use_count < num_childs and alias not in aliases_before:
@ -807,8 +785,7 @@ class Query(object):
old_alias = col[0]
return (change_map.get(old_alias, old_alias), col[1])
else:
col.relabel_aliases(change_map)
return col
return col.relabeled_clone(change_map)
# 1. Update references in "select" (normal columns plus aliases),
# "group by", "where" and "having".
self.where.relabel_aliases(change_map)