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queryset-refactor: Simplified updates of related tables, with added bonus of less bugs.

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It will be slightly less efficient in rare cases, but who cares? If anybody
needs it to be as efficient as possible they can write the query manually and
this is good enough for the other 98% or so.


git-svn-id: http://code.djangoproject.com/svn/django/branches/queryset-refactor@7190 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Malcolm Tredinnick 2008-03-03 16:36:28 +00:00
parent 22ecacda1b
commit d4d528e9b0
1 changed files with 3 additions and 15 deletions
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18
django/db/models/sql/subqueries.py
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@ -1,7 +1,6 @@
"""
Query subclasses which provide extra functionality beyond simple data retrieval.
"""
from copy import deepcopy
from django.contrib.contenttypes import generic
from django.core.exceptions import FieldError
@ -159,20 +158,9 @@ class UpdateQuery(Query):
# We need to use a sub-select in the where clause to filter on things
# from other tables.
query = self.clone(klass=Query)
main_alias = query.tables[0]
if count != 1:
query.unref_alias(main_alias)
if query.alias_map[main_alias][ALIAS_REFCOUNT]:
alias = '%s0' % self.alias_prefix
query.change_alias(main_alias, alias)
col = query.model._meta.pk.column
else:
for model in query.model._meta.get_parent_list():
for alias in query.table_map.get(model._meta.db_table, []):
if query.alias_map[alias][ALIAS_REFCOUNT]:
col = model._meta.pk.column
break
query.add_local_columns([col])
alias = '%s0' % self.alias_prefix
query.change_alias(query.tables[0], alias)
self.add_local_columns([query.model._meta.pk.column])
# Now we adjust the current query: reset the where clause and get rid
# of all the tables we don't need (since they're in the sub-select).