mirrors/django
1
0
Fork 0
mirror of https://github.com/django/django.git synced 2025-10-26 15:16:09 +00:00
Code Issues 32 Releases Wiki Activity

Fixed #12663 -- Formalized the Model._meta API for retrieving fields.

Browse Source 
Thanks to Russell Keith-Magee for mentoring this Google Summer of
Code 2014 project and everyone else who helped with the patch!
This commit is contained in:
Daniel Pyrathon
2015-01-06 19:16:35 -05:00
committed by Tim Graham
parent 749d23251b
commit fb48eb0581
58 changed files with 2851 additions and 1195 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
django/db/models/deletion.py
View File

@@ -1,4 +1,5 @@
from collections import OrderedDict
from itertools import chain
from operator import attrgetter
from django.db import connections, transaction, IntegrityError
@@ -51,6 +52,23 @@ def DO_NOTHING(collector, field, sub_objs, using):
pass
def get_candidate_relations_to_delete(opts):
# Collect models that contain candidate relations to delete. This may include
# relations coming from proxy models.
candidate_models = {opts}
candidate_models = candidate_models.union(opts.concrete_model._meta.proxied_children)
# For each model, get all candidate fields.
candidate_model_fields = chain.from_iterable(
opts.get_fields(include_hidden=True) for opts in candidate_models
)
# The candidate relations are the ones that come from N-1 and 1-1 relations.
# N-N (i.e., many-to-many) relations aren't candidates for deletion.
return (
f for f in candidate_model_fields
if f.auto_created and not f.concrete and (f.one_to_one or f.many_to_one)
)
class Collector(object):
def __init__(self, using):
self.using = using
@@ -134,8 +152,7 @@ class Collector(object):
return False
# Foreign keys pointing to this model, both from m2m and other
# models.
for related in opts.get_all_related_objects(
include_hidden=True, include_proxy_eq=True):
for related in get_candidate_relations_to_delete(opts):
if related.field.rel.on_delete is not DO_NOTHING:
return False
for field in model._meta.virtual_fields:
@@ -184,7 +201,7 @@ class Collector(object):
model = new_objs[0].__class__
# Recursively collect concrete model's parent models, but not their
# related objects. These will be found by meta.get_all_related_objects()
# related objects. These will be found by meta.get_fields()
concrete_model = model._meta.concrete_model
for ptr in six.itervalues(concrete_model._meta.parents):
if ptr:
@@ -199,8 +216,7 @@ class Collector(object):
reverse_dependency=True)
if collect_related:
for related in model._meta.get_all_related_objects(
include_hidden=True, include_proxy_eq=True):
for related in get_candidate_relations_to_delete(model._meta):
field = related.field
if field.rel.on_delete == DO_NOTHING:
continue
@@ -225,7 +241,7 @@ class Collector(object):
Gets a QuerySet of objects related to ``objs`` via the relation ``related``.
"""
return related.model._base_manager.using(self.using).filter(
return related.related_model._base_manager.using(self.using).filter(
**{"%s__in" % related.field.name: objs}
)