d818e0c9b2
This is the result of Christopher Medrela's 2013 Summer of Code project. Thanks also to Preston Holmes, Tim Graham, Anssi Kääriäinen, Florian Apolloner, and Alex Gaynor for review notes along the way. Also: Fixes #8579, fixes #3055, fixes #19844.
2141 lines
94 KiB
Python
2141 lines
94 KiB
Python
from operator import attrgetter
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from django.apps import apps
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from django.core import checks
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from django.db import connection, connections, router, transaction
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from django.db.backends import utils
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from django.db.models import signals, Q
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from django.db.models.deletion import SET_NULL, SET_DEFAULT, CASCADE
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from django.db.models.fields import (AutoField, Field, IntegerField,
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PositiveIntegerField, PositiveSmallIntegerField, FieldDoesNotExist)
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from django.db.models.lookups import IsNull
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from django.db.models.related import RelatedObject, PathInfo
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from django.db.models.query import QuerySet
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from django.db.models.sql.datastructures import Col
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from django.utils.encoding import smart_text
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from django.utils import six
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from django.utils.deprecation import RenameMethodsBase
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from django.utils.translation import ugettext_lazy as _
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from django.utils.functional import curry, cached_property
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from django.core import exceptions
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from django.apps import apps
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from django import forms
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RECURSIVE_RELATIONSHIP_CONSTANT = 'self'
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def add_lazy_relation(cls, field, relation, operation):
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"""
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Adds a lookup on ``cls`` when a related field is defined using a string,
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i.e.::
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class MyModel(Model):
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fk = ForeignKey("AnotherModel")
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This string can be:
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* RECURSIVE_RELATIONSHIP_CONSTANT (i.e. "self") to indicate a recursive
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relation.
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* The name of a model (i.e "AnotherModel") to indicate another model in
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the same app.
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* An app-label and model name (i.e. "someapp.AnotherModel") to indicate
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another model in a different app.
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If the other model hasn't yet been loaded -- almost a given if you're using
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lazy relationships -- then the relation won't be set up until the
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class_prepared signal fires at the end of model initialization.
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operation is the work that must be performed once the relation can be resolved.
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"""
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# Check for recursive relations
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if relation == RECURSIVE_RELATIONSHIP_CONSTANT:
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app_label = cls._meta.app_label
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model_name = cls.__name__
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else:
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# Look for an "app.Model" relation
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if isinstance(relation, six.string_types):
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try:
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app_label, model_name = relation.split(".")
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except ValueError:
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# If we can't split, assume a model in current app
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app_label = cls._meta.app_label
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model_name = relation
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else:
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# it's actually a model class
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app_label = relation._meta.app_label
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model_name = relation._meta.object_name
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# Try to look up the related model, and if it's already loaded resolve the
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# string right away. If get_model returns None, it means that the related
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# model isn't loaded yet, so we need to pend the relation until the class
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# is prepared.
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try:
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model = cls._meta.apps.get_registered_model(app_label, model_name)
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except LookupError:
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key = (app_label, model_name)
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value = (cls, field, operation)
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cls._meta.apps._pending_lookups.setdefault(key, []).append(value)
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else:
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operation(field, model, cls)
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def do_pending_lookups(sender, **kwargs):
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"""
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Handle any pending relations to the sending model. Sent from class_prepared.
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"""
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key = (sender._meta.app_label, sender.__name__)
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for cls, field, operation in sender._meta.apps._pending_lookups.pop(key, []):
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operation(field, sender, cls)
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signals.class_prepared.connect(do_pending_lookups)
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class RelatedField(Field):
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def check(self, **kwargs):
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errors = super(RelatedField, self).check(**kwargs)
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errors.extend(self._check_relation_model_exists())
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errors.extend(self._check_referencing_to_swapped_model())
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errors.extend(self._check_clashes())
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return errors
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def _check_relation_model_exists(self):
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rel_is_missing = self.rel.to not in apps.get_models()
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rel_is_string = isinstance(self.rel.to, six.string_types)
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model_name = self.rel.to if rel_is_string else self.rel.to._meta.object_name
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if rel_is_missing and (rel_is_string or not self.rel.to._meta.swapped):
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return [
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checks.Error(
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('The field has a relation with model %s, which '
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'has either not been installed or is abstract.') % model_name,
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hint=('Ensure that you did not misspell the model name and '
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'the model is not abstract. Does your INSTALLED_APPS '
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'setting contain the app where %s is defined?') % model_name,
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obj=self,
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id='E030',
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)
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]
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return []
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def _check_referencing_to_swapped_model(self):
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if (self.rel.to not in apps.get_models() and
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not isinstance(self.rel.to, six.string_types) and
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self.rel.to._meta.swapped):
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model = "%s.%s" % (
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self.rel.to._meta.app_label,
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self.rel.to._meta.object_name
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)
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return [
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checks.Error(
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('The field defines a relation with the model %s, '
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'which has been swapped out.') % model,
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hint='Update the relation to point at settings.%s' % self.rel.to._meta.swappable,
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obj=self,
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id='E029',
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)
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]
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return []
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def _check_clashes(self):
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""" Check accessor and reverse query name clashes. """
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from django.db.models.base import ModelBase
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errors = []
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opts = self.model._meta
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# `f.rel.to` may be a string instead of a model. Skip if model name is
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# not resolved.
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if not isinstance(self.rel.to, ModelBase):
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return []
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# If the field doesn't install backward relation on the target model (so
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# `is_hidden` returns True), then there are no clashes to check and we
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# can skip these fields.
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if self.rel.is_hidden():
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return []
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try:
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self.related
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except AttributeError:
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return []
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# Consider that we are checking field `Model.foreign` and the models
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# are:
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#
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# class Target(models.Model):
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# model = models.IntegerField()
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# model_set = models.IntegerField()
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#
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# class Model(models.Model):
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# foreign = models.ForeignKey(Target)
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# m2m = models.ManyToManyField(Target)
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rel_opts = self.rel.to._meta
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# rel_opts.object_name == "Target"
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rel_name = self.related.get_accessor_name() # i. e. "model_set"
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rel_query_name = self.related_query_name() # i. e. "model"
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field_name = "%s.%s" % (opts.object_name,
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self.name) # i. e. "Model.field"
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# Check clashes between accessor or reverse query name of `field`
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# and any other field name -- i. e. accessor for Model.foreign is
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# model_set and it clashes with Target.model_set.
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potential_clashes = rel_opts.fields + rel_opts.local_many_to_many
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for clash_field in potential_clashes:
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clash_name = "%s.%s" % (rel_opts.object_name,
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clash_field.name) # i. e. "Target.model_set"
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if clash_field.name == rel_name:
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errors.append(
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checks.Error(
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'Accessor for field %s clashes with field %s.' % (field_name, clash_name),
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hint=('Rename field %s or add/change a related_name '
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'argument to the definition for field %s.') % (clash_name, field_name),
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obj=self,
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id='E014',
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)
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)
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if clash_field.name == rel_query_name:
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errors.append(
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checks.Error(
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'Reverse query name for field %s clashes with field %s.' % (field_name, clash_name),
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hint=('Rename field %s or add/change a related_name '
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'argument to the definition for field %s.') % (clash_name, field_name),
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obj=self,
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id='E015',
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)
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)
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# Check clashes between accessors/reverse query names of `field` and
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# any other field accessor -- i. e. Model.foreign accessor clashes with
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# Model.m2m accessor.
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potential_clashes = rel_opts.get_all_related_many_to_many_objects()
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potential_clashes += rel_opts.get_all_related_objects()
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potential_clashes = (r for r in potential_clashes
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if r.field is not self)
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for clash_field in potential_clashes:
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clash_name = "%s.%s" % ( # i. e. "Model.m2m"
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clash_field.model._meta.object_name,
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clash_field.field.name)
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if clash_field.get_accessor_name() == rel_name:
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errors.append(
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checks.Error(
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'Clash between accessors for %s and %s.' % (field_name, clash_name),
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hint=('Add or change a related_name argument '
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'to the definition for %s or %s.') % (field_name, clash_name),
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obj=self,
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id='E016',
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)
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)
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if clash_field.get_accessor_name() == rel_query_name:
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errors.append(
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checks.Error(
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'Clash between reverse query names for %s and %s.' % (field_name, clash_name),
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hint=('Add or change a related_name argument '
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'to the definition for %s or %s.') % (field_name, clash_name),
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obj=self,
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id='E017',
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)
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)
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return errors
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def db_type(self, connection):
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'''By default related field will not have a column
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as it relates columns to another table'''
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return None
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def contribute_to_class(self, cls, name, virtual_only=False):
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sup = super(RelatedField, self)
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# Store the opts for related_query_name()
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self.opts = cls._meta
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if hasattr(sup, 'contribute_to_class'):
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sup.contribute_to_class(cls, name, virtual_only=virtual_only)
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if not cls._meta.abstract and self.rel.related_name:
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related_name = self.rel.related_name % {
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'class': cls.__name__.lower(),
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'app_label': cls._meta.app_label.lower()
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}
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self.rel.related_name = related_name
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other = self.rel.to
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if isinstance(other, six.string_types) or other._meta.pk is None:
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def resolve_related_class(field, model, cls):
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field.rel.to = model
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field.do_related_class(model, cls)
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add_lazy_relation(cls, self, other, resolve_related_class)
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else:
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self.do_related_class(other, cls)
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@property
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def swappable_setting(self):
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"""
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Gets the setting that this is powered from for swapping, or None
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if it's not swapped in / marked with swappable=False.
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"""
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if self.swappable:
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# Work out string form of "to"
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if isinstance(self.rel.to, six.string_types):
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to_string = self.rel.to
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else:
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to_string = "%s.%s" % (
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self.rel.to._meta.app_label,
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self.rel.to._meta.object_name,
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)
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# See if anything swapped/swappable matches
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for model in apps.get_models(include_swapped=True):
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if model._meta.swapped:
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if model._meta.swapped == to_string:
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return model._meta.swappable
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if ("%s.%s" % (model._meta.app_label, model._meta.object_name)) == to_string and model._meta.swappable:
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return model._meta.swappable
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return None
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def set_attributes_from_rel(self):
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self.name = self.name or (self.rel.to._meta.model_name + '_' + self.rel.to._meta.pk.name)
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if self.verbose_name is None:
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self.verbose_name = self.rel.to._meta.verbose_name
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self.rel.set_field_name()
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def do_related_class(self, other, cls):
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self.set_attributes_from_rel()
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self.related = RelatedObject(other, cls, self)
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if not cls._meta.abstract:
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self.contribute_to_related_class(other, self.related)
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def related_query_name(self):
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# This method defines the name that can be used to identify this
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# related object in a table-spanning query. It uses the lower-cased
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# object_name by default, but this can be overridden with the
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# "related_name" option.
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return self.rel.related_query_name or self.rel.related_name or self.opts.model_name
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class RenameRelatedObjectDescriptorMethods(RenameMethodsBase):
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renamed_methods = (
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('get_query_set', 'get_queryset', DeprecationWarning),
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('get_prefetch_query_set', 'get_prefetch_queryset', DeprecationWarning),
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)
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class SingleRelatedObjectDescriptor(six.with_metaclass(RenameRelatedObjectDescriptorMethods)):
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# This class provides the functionality that makes the related-object
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# managers available as attributes on a model class, for fields that have
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# a single "remote" value, on the class pointed to by a related field.
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# In the example "place.restaurant", the restaurant attribute is a
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# SingleRelatedObjectDescriptor instance.
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def __init__(self, related):
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self.related = related
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self.cache_name = related.get_cache_name()
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@cached_property
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def RelatedObjectDoesNotExist(self):
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# The exception isn't created at initialization time for the sake of
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# consistency with `ReverseSingleRelatedObjectDescriptor`.
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return type(
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str('RelatedObjectDoesNotExist'),
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(self.related.model.DoesNotExist, AttributeError),
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{}
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)
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def is_cached(self, instance):
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return hasattr(instance, self.cache_name)
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def get_queryset(self, **hints):
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return self.related.model._base_manager.db_manager(hints=hints)
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def get_prefetch_queryset(self, instances, queryset=None):
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if queryset is not None:
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raise ValueError("Custom queryset can't be used for this lookup.")
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rel_obj_attr = attrgetter(self.related.field.attname)
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instance_attr = lambda obj: obj._get_pk_val()
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instances_dict = dict((instance_attr(inst), inst) for inst in instances)
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query = {'%s__in' % self.related.field.name: instances}
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qs = self.get_queryset(instance=instances[0]).filter(**query)
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# Since we're going to assign directly in the cache,
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# we must manage the reverse relation cache manually.
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rel_obj_cache_name = self.related.field.get_cache_name()
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for rel_obj in qs:
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instance = instances_dict[rel_obj_attr(rel_obj)]
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setattr(rel_obj, rel_obj_cache_name, instance)
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return qs, rel_obj_attr, instance_attr, True, self.cache_name
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def __get__(self, instance, instance_type=None):
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if instance is None:
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return self
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try:
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rel_obj = getattr(instance, self.cache_name)
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except AttributeError:
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related_pk = instance._get_pk_val()
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if related_pk is None:
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rel_obj = None
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else:
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params = {}
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for lh_field, rh_field in self.related.field.related_fields:
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params['%s__%s' % (self.related.field.name, rh_field.name)] = getattr(instance, rh_field.attname)
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try:
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rel_obj = self.get_queryset(instance=instance).get(**params)
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except self.related.model.DoesNotExist:
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rel_obj = None
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else:
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setattr(rel_obj, self.related.field.get_cache_name(), instance)
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setattr(instance, self.cache_name, rel_obj)
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if rel_obj is None:
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raise self.RelatedObjectDoesNotExist(
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"%s has no %s." % (
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instance.__class__.__name__,
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self.related.get_accessor_name()
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)
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)
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else:
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return rel_obj
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def __set__(self, instance, value):
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# The similarity of the code below to the code in
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# ReverseSingleRelatedObjectDescriptor is annoying, but there's a bunch
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# of small differences that would make a common base class convoluted.
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# If null=True, we can assign null here, but otherwise the value needs
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# to be an instance of the related class.
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if value is None and self.related.field.null is False:
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raise ValueError(
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'Cannot assign None: "%s.%s" does not allow null values.' % (
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instance._meta.object_name,
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self.related.get_accessor_name(),
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)
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)
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elif value is not None and not isinstance(value, self.related.model):
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raise ValueError(
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'Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (
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value,
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instance._meta.object_name,
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self.related.get_accessor_name(),
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self.related.opts.object_name,
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)
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)
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elif value is not None:
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if instance._state.db is None:
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instance._state.db = router.db_for_write(instance.__class__, instance=value)
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elif value._state.db is None:
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value._state.db = router.db_for_write(value.__class__, instance=instance)
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elif value._state.db is not None and instance._state.db is not None:
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if not router.allow_relation(value, instance):
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raise ValueError('Cannot assign "%r": the current database router prevents this relation.' % value)
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related_pk = tuple(getattr(instance, field.attname) for field in self.related.field.foreign_related_fields)
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if None in related_pk:
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raise ValueError(
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'Cannot assign "%r": "%s" instance isn\'t saved in the database.' %
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(value, instance._meta.object_name)
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)
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# Set the value of the related field to the value of the related object's related field
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for index, field in enumerate(self.related.field.local_related_fields):
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setattr(value, field.attname, related_pk[index])
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# Since we already know what the related object is, seed the related
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# object caches now, too. This avoids another db hit if you get the
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# object you just set.
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setattr(instance, self.cache_name, value)
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setattr(value, self.related.field.get_cache_name(), instance)
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|
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class ReverseSingleRelatedObjectDescriptor(six.with_metaclass(RenameRelatedObjectDescriptorMethods)):
|
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# This class provides the functionality that makes the related-object
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# managers available as attributes on a model class, for fields that have
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# a single "remote" value, on the class that defines the related field.
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# In the example "choice.poll", the poll attribute is a
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# ReverseSingleRelatedObjectDescriptor instance.
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def __init__(self, field_with_rel):
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self.field = field_with_rel
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self.cache_name = self.field.get_cache_name()
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@cached_property
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def RelatedObjectDoesNotExist(self):
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# The exception can't be created at initialization time since the
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# related model might not be resolved yet; `rel.to` might still be
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# a string model reference.
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return type(
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str('RelatedObjectDoesNotExist'),
|
|
(self.field.rel.to.DoesNotExist, AttributeError),
|
|
{}
|
|
)
|
|
|
|
def is_cached(self, instance):
|
|
return hasattr(instance, self.cache_name)
|
|
|
|
def get_queryset(self, **hints):
|
|
rel_mgr = self.field.rel.to._default_manager.db_manager(hints=hints)
|
|
# If the related manager indicates that it should be used for
|
|
# related fields, respect that.
|
|
if getattr(rel_mgr, 'use_for_related_fields', False):
|
|
return rel_mgr
|
|
else:
|
|
return QuerySet(self.field.rel.to, hints=hints)
|
|
|
|
def get_prefetch_queryset(self, instances, queryset=None):
|
|
if queryset is not None:
|
|
raise ValueError("Custom queryset can't be used for this lookup.")
|
|
|
|
rel_obj_attr = self.field.get_foreign_related_value
|
|
instance_attr = self.field.get_local_related_value
|
|
instances_dict = dict((instance_attr(inst), inst) for inst in instances)
|
|
related_field = self.field.foreign_related_fields[0]
|
|
|
|
# FIXME: This will need to be revisited when we introduce support for
|
|
# composite fields. In the meantime we take this practical approach to
|
|
# solve a regression on 1.6 when the reverse manager in hidden
|
|
# (related_name ends with a '+'). Refs #21410.
|
|
if self.field.rel.is_hidden():
|
|
query = {'%s__in' % related_field.name: set(instance_attr(inst)[0] for inst in instances)}
|
|
else:
|
|
query = {'%s__in' % self.field.related_query_name(): instances}
|
|
|
|
qs = self.get_queryset(instance=instances[0]).filter(**query)
|
|
# Since we're going to assign directly in the cache,
|
|
# we must manage the reverse relation cache manually.
|
|
if not self.field.rel.multiple:
|
|
rel_obj_cache_name = self.field.related.get_cache_name()
|
|
for rel_obj in qs:
|
|
instance = instances_dict[rel_obj_attr(rel_obj)]
|
|
setattr(rel_obj, rel_obj_cache_name, instance)
|
|
return qs, rel_obj_attr, instance_attr, True, self.cache_name
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
try:
|
|
rel_obj = getattr(instance, self.cache_name)
|
|
except AttributeError:
|
|
val = self.field.get_local_related_value(instance)
|
|
if None in val:
|
|
rel_obj = None
|
|
else:
|
|
params = dict(
|
|
(rh_field.attname, getattr(instance, lh_field.attname))
|
|
for lh_field, rh_field in self.field.related_fields)
|
|
qs = self.get_queryset(instance=instance)
|
|
extra_filter = self.field.get_extra_descriptor_filter(instance)
|
|
if isinstance(extra_filter, dict):
|
|
params.update(extra_filter)
|
|
qs = qs.filter(**params)
|
|
else:
|
|
qs = qs.filter(extra_filter, **params)
|
|
# Assuming the database enforces foreign keys, this won't fail.
|
|
rel_obj = qs.get()
|
|
if not self.field.rel.multiple:
|
|
setattr(rel_obj, self.field.related.get_cache_name(), instance)
|
|
setattr(instance, self.cache_name, rel_obj)
|
|
if rel_obj is None and not self.field.null:
|
|
raise self.RelatedObjectDoesNotExist(
|
|
"%s has no %s." % (self.field.model.__name__, self.field.name)
|
|
)
|
|
else:
|
|
return rel_obj
|
|
|
|
def __set__(self, instance, value):
|
|
# If null=True, we can assign null here, but otherwise the value needs
|
|
# to be an instance of the related class.
|
|
if value is None and self.field.null is False:
|
|
raise ValueError(
|
|
'Cannot assign None: "%s.%s" does not allow null values.' %
|
|
(instance._meta.object_name, self.field.name)
|
|
)
|
|
elif value is not None and not isinstance(value, self.field.rel.to):
|
|
raise ValueError(
|
|
'Cannot assign "%r": "%s.%s" must be a "%s" instance.' % (
|
|
value,
|
|
instance._meta.object_name,
|
|
self.field.name,
|
|
self.field.rel.to._meta.object_name,
|
|
)
|
|
)
|
|
elif value is not None:
|
|
if instance._state.db is None:
|
|
instance._state.db = router.db_for_write(instance.__class__, instance=value)
|
|
elif value._state.db is None:
|
|
value._state.db = router.db_for_write(value.__class__, instance=instance)
|
|
elif value._state.db is not None and instance._state.db is not None:
|
|
if not router.allow_relation(value, instance):
|
|
raise ValueError('Cannot assign "%r": the current database router prevents this relation.' % value)
|
|
|
|
# If we're setting the value of a OneToOneField to None, we need to clear
|
|
# out the cache on any old related object. Otherwise, deleting the
|
|
# previously-related object will also cause this object to be deleted,
|
|
# which is wrong.
|
|
if value is None:
|
|
# Look up the previously-related object, which may still be available
|
|
# since we've not yet cleared out the related field.
|
|
# Use the cache directly, instead of the accessor; if we haven't
|
|
# populated the cache, then we don't care - we're only accessing
|
|
# the object to invalidate the accessor cache, so there's no
|
|
# need to populate the cache just to expire it again.
|
|
related = getattr(instance, self.cache_name, None)
|
|
|
|
# If we've got an old related object, we need to clear out its
|
|
# cache. This cache also might not exist if the related object
|
|
# hasn't been accessed yet.
|
|
if related is not None:
|
|
setattr(related, self.field.related.get_cache_name(), None)
|
|
|
|
# Set the value of the related field
|
|
for lh_field, rh_field in self.field.related_fields:
|
|
try:
|
|
setattr(instance, lh_field.attname, getattr(value, rh_field.attname))
|
|
except AttributeError:
|
|
setattr(instance, lh_field.attname, None)
|
|
|
|
# Since we already know what the related object is, seed the related
|
|
# object caches now, too. This avoids another db hit if you get the
|
|
# object you just set.
|
|
setattr(instance, self.cache_name, value)
|
|
if value is not None and not self.field.rel.multiple:
|
|
setattr(value, self.field.related.get_cache_name(), instance)
|
|
|
|
|
|
def create_foreign_related_manager(superclass, rel_field, rel_model):
|
|
class RelatedManager(superclass):
|
|
def __init__(self, instance):
|
|
super(RelatedManager, self).__init__()
|
|
self.instance = instance
|
|
self.core_filters = {'%s__exact' % rel_field.name: instance}
|
|
self.model = rel_model
|
|
|
|
def __call__(self, **kwargs):
|
|
# We use **kwargs rather than a kwarg argument to enforce the
|
|
# `manager='manager_name'` syntax.
|
|
manager = getattr(self.model, kwargs.pop('manager'))
|
|
manager_class = create_foreign_related_manager(manager.__class__, rel_field, rel_model)
|
|
return manager_class(self.instance)
|
|
do_not_call_in_templates = True
|
|
|
|
def get_queryset(self):
|
|
try:
|
|
return self.instance._prefetched_objects_cache[rel_field.related_query_name()]
|
|
except (AttributeError, KeyError):
|
|
db = self._db or router.db_for_read(self.model, instance=self.instance)
|
|
empty_strings_as_null = connections[db].features.interprets_empty_strings_as_nulls
|
|
qs = super(RelatedManager, self).get_queryset()
|
|
qs._add_hints(instance=self.instance)
|
|
if self._db:
|
|
qs = qs.using(self._db)
|
|
qs = qs.filter(**self.core_filters)
|
|
for field in rel_field.foreign_related_fields:
|
|
val = getattr(self.instance, field.attname)
|
|
if val is None or (val == '' and empty_strings_as_null):
|
|
return qs.none()
|
|
qs._known_related_objects = {rel_field: {self.instance.pk: self.instance}}
|
|
return qs
|
|
|
|
def get_prefetch_queryset(self, instances, queryset=None):
|
|
if queryset is None:
|
|
queryset = super(RelatedManager, self).get_queryset()
|
|
|
|
queryset._add_hints(instance=instances[0])
|
|
queryset = queryset.using(queryset._db or self._db)
|
|
|
|
rel_obj_attr = rel_field.get_local_related_value
|
|
instance_attr = rel_field.get_foreign_related_value
|
|
instances_dict = dict((instance_attr(inst), inst) for inst in instances)
|
|
query = {'%s__in' % rel_field.name: instances}
|
|
queryset = queryset.filter(**query)
|
|
|
|
# Since we just bypassed this class' get_queryset(), we must manage
|
|
# the reverse relation manually.
|
|
for rel_obj in queryset:
|
|
instance = instances_dict[rel_obj_attr(rel_obj)]
|
|
setattr(rel_obj, rel_field.name, instance)
|
|
cache_name = rel_field.related_query_name()
|
|
return queryset, rel_obj_attr, instance_attr, False, cache_name
|
|
|
|
def add(self, *objs):
|
|
objs = list(objs)
|
|
db = router.db_for_write(self.model, instance=self.instance)
|
|
with transaction.commit_on_success_unless_managed(
|
|
using=db, savepoint=False):
|
|
for obj in objs:
|
|
if not isinstance(obj, self.model):
|
|
raise TypeError("'%s' instance expected, got %r" %
|
|
(self.model._meta.object_name, obj))
|
|
setattr(obj, rel_field.name, self.instance)
|
|
obj.save()
|
|
add.alters_data = True
|
|
|
|
def create(self, **kwargs):
|
|
kwargs[rel_field.name] = self.instance
|
|
db = router.db_for_write(self.model, instance=self.instance)
|
|
return super(RelatedManager, self.db_manager(db)).create(**kwargs)
|
|
create.alters_data = True
|
|
|
|
def get_or_create(self, **kwargs):
|
|
# Update kwargs with the related object that this
|
|
# ForeignRelatedObjectsDescriptor knows about.
|
|
kwargs[rel_field.name] = self.instance
|
|
db = router.db_for_write(self.model, instance=self.instance)
|
|
return super(RelatedManager, self.db_manager(db)).get_or_create(**kwargs)
|
|
get_or_create.alters_data = True
|
|
|
|
# remove() and clear() are only provided if the ForeignKey can have a value of null.
|
|
if rel_field.null:
|
|
def remove(self, *objs, **kwargs):
|
|
if not objs:
|
|
return
|
|
bulk = kwargs.pop('bulk', True)
|
|
val = rel_field.get_foreign_related_value(self.instance)
|
|
old_ids = set()
|
|
for obj in objs:
|
|
# Is obj actually part of this descriptor set?
|
|
if rel_field.get_local_related_value(obj) == val:
|
|
old_ids.add(obj.pk)
|
|
else:
|
|
raise rel_field.rel.to.DoesNotExist("%r is not related to %r." % (obj, self.instance))
|
|
self._clear(self.filter(pk__in=old_ids), bulk)
|
|
remove.alters_data = True
|
|
|
|
def clear(self, **kwargs):
|
|
bulk = kwargs.pop('bulk', True)
|
|
self._clear(self, bulk)
|
|
clear.alters_data = True
|
|
|
|
def _clear(self, queryset, bulk):
|
|
db = router.db_for_write(self.model, instance=self.instance)
|
|
queryset = queryset.using(db)
|
|
if bulk:
|
|
queryset.update(**{rel_field.name: None})
|
|
else:
|
|
with transaction.commit_on_success_unless_managed(using=db, savepoint=False):
|
|
for obj in queryset:
|
|
setattr(obj, rel_field.name, None)
|
|
obj.save(update_fields=[rel_field.name])
|
|
_clear.alters_data = True
|
|
|
|
return RelatedManager
|
|
|
|
|
|
class ForeignRelatedObjectsDescriptor(object):
|
|
# This class provides the functionality that makes the related-object
|
|
# managers available as attributes on a model class, for fields that have
|
|
# multiple "remote" values and have a ForeignKey pointed at them by
|
|
# some other model. In the example "poll.choice_set", the choice_set
|
|
# attribute is a ForeignRelatedObjectsDescriptor instance.
|
|
def __init__(self, related):
|
|
self.related = related # RelatedObject instance
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
|
|
return self.related_manager_cls(instance)
|
|
|
|
def __set__(self, instance, value):
|
|
manager = self.__get__(instance)
|
|
# If the foreign key can support nulls, then completely clear the related set.
|
|
# Otherwise, just move the named objects into the set.
|
|
if self.related.field.null:
|
|
manager.clear()
|
|
manager.add(*value)
|
|
|
|
@cached_property
|
|
def related_manager_cls(self):
|
|
# Dynamically create a class that subclasses the related model's default
|
|
# manager.
|
|
return create_foreign_related_manager(
|
|
self.related.model._default_manager.__class__,
|
|
self.related.field,
|
|
self.related.model,
|
|
)
|
|
|
|
|
|
def create_many_related_manager(superclass, rel):
|
|
"""Creates a manager that subclasses 'superclass' (which is a Manager)
|
|
and adds behavior for many-to-many related objects."""
|
|
class ManyRelatedManager(superclass):
|
|
def __init__(self, model=None, query_field_name=None, instance=None, symmetrical=None,
|
|
source_field_name=None, target_field_name=None, reverse=False,
|
|
through=None, prefetch_cache_name=None):
|
|
super(ManyRelatedManager, self).__init__()
|
|
self.model = model
|
|
self.query_field_name = query_field_name
|
|
|
|
source_field = through._meta.get_field(source_field_name)
|
|
source_related_fields = source_field.related_fields
|
|
|
|
self.core_filters = {}
|
|
for lh_field, rh_field in source_related_fields:
|
|
self.core_filters['%s__%s' % (query_field_name, rh_field.name)] = getattr(instance, rh_field.attname)
|
|
|
|
self.instance = instance
|
|
self.symmetrical = symmetrical
|
|
self.source_field = source_field
|
|
self.target_field = through._meta.get_field(target_field_name)
|
|
self.source_field_name = source_field_name
|
|
self.target_field_name = target_field_name
|
|
self.reverse = reverse
|
|
self.through = through
|
|
self.prefetch_cache_name = prefetch_cache_name
|
|
self.related_val = source_field.get_foreign_related_value(instance)
|
|
if None in self.related_val:
|
|
raise ValueError('"%r" needs to have a value for field "%s" before '
|
|
'this many-to-many relationship can be used.' %
|
|
(instance, source_field_name))
|
|
# Even if this relation is not to pk, we require still pk value.
|
|
# The wish is that the instance has been already saved to DB,
|
|
# although having a pk value isn't a guarantee of that.
|
|
if instance.pk is None:
|
|
raise ValueError("%r instance needs to have a primary key value before "
|
|
"a many-to-many relationship can be used." %
|
|
instance.__class__.__name__)
|
|
|
|
def __call__(self, **kwargs):
|
|
# We use **kwargs rather than a kwarg argument to enforce the
|
|
# `manager='manager_name'` syntax.
|
|
manager = getattr(self.model, kwargs.pop('manager'))
|
|
manager_class = create_many_related_manager(manager.__class__, rel)
|
|
return manager_class(
|
|
model=self.model,
|
|
query_field_name=self.query_field_name,
|
|
instance=self.instance,
|
|
symmetrical=self.symmetrical,
|
|
source_field_name=self.source_field_name,
|
|
target_field_name=self.target_field_name,
|
|
reverse=self.reverse,
|
|
through=self.through,
|
|
prefetch_cache_name=self.prefetch_cache_name,
|
|
)
|
|
do_not_call_in_templates = True
|
|
|
|
def _build_remove_filters(self, removed_vals):
|
|
filters = Q(**{self.source_field_name: self.related_val})
|
|
# No need to add a subquery condition if removed_vals is a QuerySet without
|
|
# filters.
|
|
removed_vals_filters = (not isinstance(removed_vals, QuerySet) or
|
|
removed_vals._has_filters())
|
|
if removed_vals_filters:
|
|
filters &= Q(**{'%s__in' % self.target_field_name: removed_vals})
|
|
if self.symmetrical:
|
|
symmetrical_filters = Q(**{self.target_field_name: self.related_val})
|
|
if removed_vals_filters:
|
|
symmetrical_filters &= Q(
|
|
**{'%s__in' % self.source_field_name: removed_vals})
|
|
filters |= symmetrical_filters
|
|
return filters
|
|
|
|
def get_queryset(self):
|
|
try:
|
|
return self.instance._prefetched_objects_cache[self.prefetch_cache_name]
|
|
except (AttributeError, KeyError):
|
|
qs = super(ManyRelatedManager, self).get_queryset()
|
|
qs._add_hints(instance=self.instance)
|
|
if self._db:
|
|
qs = qs.using(self._db)
|
|
return qs._next_is_sticky().filter(**self.core_filters)
|
|
|
|
def get_prefetch_queryset(self, instances, queryset=None):
|
|
if queryset is None:
|
|
queryset = super(ManyRelatedManager, self).get_queryset()
|
|
|
|
queryset._add_hints(instance=instances[0])
|
|
queryset = queryset.using(queryset._db or self._db)
|
|
|
|
query = {'%s__in' % self.query_field_name: instances}
|
|
queryset = queryset._next_is_sticky().filter(**query)
|
|
|
|
# M2M: need to annotate the query in order to get the primary model
|
|
# that the secondary model was actually related to. We know that
|
|
# there will already be a join on the join table, so we can just add
|
|
# the select.
|
|
|
|
# For non-autocreated 'through' models, can't assume we are
|
|
# dealing with PK values.
|
|
fk = self.through._meta.get_field(self.source_field_name)
|
|
join_table = self.through._meta.db_table
|
|
connection = connections[queryset.db]
|
|
qn = connection.ops.quote_name
|
|
queryset = queryset.extra(select=dict(
|
|
('_prefetch_related_val_%s' % f.attname,
|
|
'%s.%s' % (qn(join_table), qn(f.column))) for f in fk.local_related_fields))
|
|
return (queryset,
|
|
lambda result: tuple(getattr(result, '_prefetch_related_val_%s' % f.attname) for f in fk.local_related_fields),
|
|
lambda inst: tuple(getattr(inst, f.attname) for f in fk.foreign_related_fields),
|
|
False,
|
|
self.prefetch_cache_name)
|
|
|
|
# If the ManyToMany relation has an intermediary model,
|
|
# the add and remove methods do not exist.
|
|
if rel.through._meta.auto_created:
|
|
def add(self, *objs):
|
|
self._add_items(self.source_field_name, self.target_field_name, *objs)
|
|
|
|
# If this is a symmetrical m2m relation to self, add the mirror entry in the m2m table
|
|
if self.symmetrical:
|
|
self._add_items(self.target_field_name, self.source_field_name, *objs)
|
|
add.alters_data = True
|
|
|
|
def remove(self, *objs):
|
|
self._remove_items(self.source_field_name, self.target_field_name, *objs)
|
|
remove.alters_data = True
|
|
|
|
def clear(self):
|
|
db = router.db_for_write(self.through, instance=self.instance)
|
|
|
|
signals.m2m_changed.send(sender=self.through, action="pre_clear",
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=None, using=db)
|
|
|
|
filters = self._build_remove_filters(super(ManyRelatedManager, self).get_queryset().using(db))
|
|
self.through._default_manager.using(db).filter(filters).delete()
|
|
|
|
signals.m2m_changed.send(sender=self.through, action="post_clear",
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=None, using=db)
|
|
clear.alters_data = True
|
|
|
|
def create(self, **kwargs):
|
|
# This check needs to be done here, since we can't later remove this
|
|
# from the method lookup table, as we do with add and remove.
|
|
if not self.through._meta.auto_created:
|
|
opts = self.through._meta
|
|
raise AttributeError(
|
|
"Cannot use create() on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." %
|
|
(opts.app_label, opts.object_name)
|
|
)
|
|
db = router.db_for_write(self.instance.__class__, instance=self.instance)
|
|
new_obj = super(ManyRelatedManager, self.db_manager(db)).create(**kwargs)
|
|
self.add(new_obj)
|
|
return new_obj
|
|
create.alters_data = True
|
|
|
|
def get_or_create(self, **kwargs):
|
|
db = router.db_for_write(self.instance.__class__, instance=self.instance)
|
|
obj, created = \
|
|
super(ManyRelatedManager, self.db_manager(db)).get_or_create(**kwargs)
|
|
# We only need to add() if created because if we got an object back
|
|
# from get() then the relationship already exists.
|
|
if created:
|
|
self.add(obj)
|
|
return obj, created
|
|
get_or_create.alters_data = True
|
|
|
|
def _add_items(self, source_field_name, target_field_name, *objs):
|
|
# source_field_name: the PK fieldname in join table for the source object
|
|
# target_field_name: the PK fieldname in join table for the target object
|
|
# *objs - objects to add. Either object instances, or primary keys of object instances.
|
|
|
|
# If there aren't any objects, there is nothing to do.
|
|
from django.db.models import Model
|
|
if objs:
|
|
new_ids = set()
|
|
for obj in objs:
|
|
if isinstance(obj, self.model):
|
|
if not router.allow_relation(obj, self.instance):
|
|
raise ValueError(
|
|
'Cannot add "%r": instance is on database "%s", value is on database "%s"' %
|
|
(obj, self.instance._state.db, obj._state.db)
|
|
)
|
|
fk_val = self.through._meta.get_field(
|
|
target_field_name).get_foreign_related_value(obj)[0]
|
|
if fk_val is None:
|
|
raise ValueError(
|
|
'Cannot add "%r": the value for field "%s" is None' %
|
|
(obj, target_field_name)
|
|
)
|
|
new_ids.add(fk_val)
|
|
elif isinstance(obj, Model):
|
|
raise TypeError(
|
|
"'%s' instance expected, got %r" %
|
|
(self.model._meta.object_name, obj)
|
|
)
|
|
else:
|
|
new_ids.add(obj)
|
|
db = router.db_for_write(self.through, instance=self.instance)
|
|
vals = self.through._default_manager.using(db).values_list(target_field_name, flat=True)
|
|
vals = vals.filter(**{
|
|
source_field_name: self.related_val[0],
|
|
'%s__in' % target_field_name: new_ids,
|
|
})
|
|
new_ids = new_ids - set(vals)
|
|
|
|
if self.reverse or source_field_name == self.source_field_name:
|
|
# Don't send the signal when we are inserting the
|
|
# duplicate data row for symmetrical reverse entries.
|
|
signals.m2m_changed.send(sender=self.through, action='pre_add',
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=new_ids, using=db)
|
|
# Add the ones that aren't there already
|
|
self.through._default_manager.using(db).bulk_create([
|
|
self.through(**{
|
|
'%s_id' % source_field_name: self.related_val[0],
|
|
'%s_id' % target_field_name: obj_id,
|
|
})
|
|
for obj_id in new_ids
|
|
])
|
|
|
|
if self.reverse or source_field_name == self.source_field_name:
|
|
# Don't send the signal when we are inserting the
|
|
# duplicate data row for symmetrical reverse entries.
|
|
signals.m2m_changed.send(sender=self.through, action='post_add',
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=new_ids, using=db)
|
|
|
|
def _remove_items(self, source_field_name, target_field_name, *objs):
|
|
# source_field_name: the PK colname in join table for the source object
|
|
# target_field_name: the PK colname in join table for the target object
|
|
# *objs - objects to remove
|
|
if not objs:
|
|
return
|
|
|
|
# Check that all the objects are of the right type
|
|
old_ids = set()
|
|
for obj in objs:
|
|
if isinstance(obj, self.model):
|
|
fk_val = self.target_field.get_foreign_related_value(obj)[0]
|
|
old_ids.add(fk_val)
|
|
else:
|
|
old_ids.add(obj)
|
|
|
|
db = router.db_for_write(self.through, instance=self.instance)
|
|
|
|
# Send a signal to the other end if need be.
|
|
signals.m2m_changed.send(sender=self.through, action="pre_remove",
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=old_ids, using=db)
|
|
target_model_qs = super(ManyRelatedManager, self).get_queryset()
|
|
if target_model_qs._has_filters():
|
|
old_vals = target_model_qs.using(db).filter(**{
|
|
'%s__in' % self.target_field.related_field.attname: old_ids})
|
|
else:
|
|
old_vals = old_ids
|
|
filters = self._build_remove_filters(old_vals)
|
|
self.through._default_manager.using(db).filter(filters).delete()
|
|
|
|
signals.m2m_changed.send(sender=self.through, action="post_remove",
|
|
instance=self.instance, reverse=self.reverse,
|
|
model=self.model, pk_set=old_ids, using=db)
|
|
|
|
return ManyRelatedManager
|
|
|
|
|
|
class ManyRelatedObjectsDescriptor(object):
|
|
# This class provides the functionality that makes the related-object
|
|
# managers available as attributes on a model class, for fields that have
|
|
# multiple "remote" values and have a ManyToManyField pointed at them by
|
|
# some other model (rather than having a ManyToManyField themselves).
|
|
# In the example "publication.article_set", the article_set attribute is a
|
|
# ManyRelatedObjectsDescriptor instance.
|
|
def __init__(self, related):
|
|
self.related = related # RelatedObject instance
|
|
|
|
@cached_property
|
|
def related_manager_cls(self):
|
|
# Dynamically create a class that subclasses the related
|
|
# model's default manager.
|
|
return create_many_related_manager(
|
|
self.related.model._default_manager.__class__,
|
|
self.related.field.rel
|
|
)
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
|
|
rel_model = self.related.model
|
|
|
|
manager = self.related_manager_cls(
|
|
model=rel_model,
|
|
query_field_name=self.related.field.name,
|
|
prefetch_cache_name=self.related.field.related_query_name(),
|
|
instance=instance,
|
|
symmetrical=False,
|
|
source_field_name=self.related.field.m2m_reverse_field_name(),
|
|
target_field_name=self.related.field.m2m_field_name(),
|
|
reverse=True,
|
|
through=self.related.field.rel.through,
|
|
)
|
|
|
|
return manager
|
|
|
|
def __set__(self, instance, value):
|
|
if not self.related.field.rel.through._meta.auto_created:
|
|
opts = self.related.field.rel.through._meta
|
|
raise AttributeError("Cannot set values on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." % (opts.app_label, opts.object_name))
|
|
|
|
manager = self.__get__(instance)
|
|
manager.clear()
|
|
manager.add(*value)
|
|
|
|
|
|
class ReverseManyRelatedObjectsDescriptor(object):
|
|
# This class provides the functionality that makes the related-object
|
|
# managers available as attributes on a model class, for fields that have
|
|
# multiple "remote" values and have a ManyToManyField defined in their
|
|
# model (rather than having another model pointed *at* them).
|
|
# In the example "article.publications", the publications attribute is a
|
|
# ReverseManyRelatedObjectsDescriptor instance.
|
|
def __init__(self, m2m_field):
|
|
self.field = m2m_field
|
|
|
|
@property
|
|
def through(self):
|
|
# through is provided so that you have easy access to the through
|
|
# model (Book.authors.through) for inlines, etc. This is done as
|
|
# a property to ensure that the fully resolved value is returned.
|
|
return self.field.rel.through
|
|
|
|
@cached_property
|
|
def related_manager_cls(self):
|
|
# Dynamically create a class that subclasses the related model's
|
|
# default manager.
|
|
return create_many_related_manager(
|
|
self.field.rel.to._default_manager.__class__,
|
|
self.field.rel
|
|
)
|
|
|
|
def __get__(self, instance, instance_type=None):
|
|
if instance is None:
|
|
return self
|
|
|
|
manager = self.related_manager_cls(
|
|
model=self.field.rel.to,
|
|
query_field_name=self.field.related_query_name(),
|
|
prefetch_cache_name=self.field.name,
|
|
instance=instance,
|
|
symmetrical=self.field.rel.symmetrical,
|
|
source_field_name=self.field.m2m_field_name(),
|
|
target_field_name=self.field.m2m_reverse_field_name(),
|
|
reverse=False,
|
|
through=self.field.rel.through,
|
|
)
|
|
|
|
return manager
|
|
|
|
def __set__(self, instance, value):
|
|
if not self.field.rel.through._meta.auto_created:
|
|
opts = self.field.rel.through._meta
|
|
raise AttributeError("Cannot set values on a ManyToManyField which specifies an intermediary model. Use %s.%s's Manager instead." % (opts.app_label, opts.object_name))
|
|
|
|
manager = self.__get__(instance)
|
|
# clear() can change expected output of 'value' queryset, we force evaluation
|
|
# of queryset before clear; ticket #19816
|
|
value = tuple(value)
|
|
manager.clear()
|
|
manager.add(*value)
|
|
|
|
|
|
class ForeignObjectRel(object):
|
|
def __init__(self, field, to, related_name=None, limit_choices_to=None,
|
|
parent_link=False, on_delete=None, related_query_name=None):
|
|
try:
|
|
to._meta
|
|
except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
|
|
assert isinstance(to, six.string_types), "'to' must be either a model, a model name or the string %r" % RECURSIVE_RELATIONSHIP_CONSTANT
|
|
|
|
self.field = field
|
|
self.to = to
|
|
self.related_name = related_name
|
|
self.related_query_name = related_query_name
|
|
self.limit_choices_to = {} if limit_choices_to is None else limit_choices_to
|
|
self.multiple = True
|
|
self.parent_link = parent_link
|
|
self.on_delete = on_delete
|
|
|
|
def is_hidden(self):
|
|
"Should the related object be hidden?"
|
|
return self.related_name and self.related_name[-1] == '+'
|
|
|
|
def get_joining_columns(self):
|
|
return self.field.get_reverse_joining_columns()
|
|
|
|
def get_extra_restriction(self, where_class, alias, related_alias):
|
|
return self.field.get_extra_restriction(where_class, related_alias, alias)
|
|
|
|
def set_field_name(self):
|
|
"""
|
|
Sets the related field's name, this is not available until later stages
|
|
of app loading, so set_field_name is called from
|
|
set_attributes_from_rel()
|
|
"""
|
|
# By default foreign object doesn't relate to any remote field (for
|
|
# example custom multicolumn joins currently have no remote field).
|
|
self.field_name = None
|
|
|
|
def get_lookup_constraint(self, constraint_class, alias, targets, sources, lookup_type,
|
|
raw_value):
|
|
return self.field.get_lookup_constraint(constraint_class, alias, targets, sources,
|
|
lookup_type, raw_value)
|
|
|
|
|
|
class ManyToOneRel(ForeignObjectRel):
|
|
def __init__(self, field, to, field_name, related_name=None, limit_choices_to=None,
|
|
parent_link=False, on_delete=None, related_query_name=None):
|
|
super(ManyToOneRel, self).__init__(
|
|
field, to, related_name=related_name, limit_choices_to=limit_choices_to,
|
|
parent_link=parent_link, on_delete=on_delete, related_query_name=related_query_name)
|
|
self.field_name = field_name
|
|
|
|
def get_related_field(self):
|
|
"""
|
|
Returns the Field in the 'to' object to which this relationship is
|
|
tied.
|
|
"""
|
|
data = self.to._meta.get_field_by_name(self.field_name)
|
|
if not data[2]:
|
|
raise FieldDoesNotExist("No related field named '%s'" %
|
|
self.field_name)
|
|
return data[0]
|
|
|
|
def set_field_name(self):
|
|
self.field_name = self.field_name or self.to._meta.pk.name
|
|
|
|
|
|
class OneToOneRel(ManyToOneRel):
|
|
def __init__(self, field, to, field_name, related_name=None, limit_choices_to=None,
|
|
parent_link=False, on_delete=None, related_query_name=None):
|
|
super(OneToOneRel, self).__init__(field, to, field_name,
|
|
related_name=related_name, limit_choices_to=limit_choices_to,
|
|
parent_link=parent_link, on_delete=on_delete, related_query_name=related_query_name)
|
|
self.multiple = False
|
|
|
|
|
|
class ManyToManyRel(object):
|
|
def __init__(self, to, related_name=None, limit_choices_to=None,
|
|
symmetrical=True, through=None, db_constraint=True, related_query_name=None):
|
|
if through and not db_constraint:
|
|
raise ValueError("Can't supply a through model and db_constraint=False")
|
|
self.to = to
|
|
self.related_name = related_name
|
|
self.related_query_name = related_query_name
|
|
if limit_choices_to is None:
|
|
limit_choices_to = {}
|
|
self.limit_choices_to = limit_choices_to
|
|
self.symmetrical = symmetrical
|
|
self.multiple = True
|
|
self.through = through
|
|
self.db_constraint = db_constraint
|
|
|
|
def is_hidden(self):
|
|
"Should the related object be hidden?"
|
|
return self.related_name and self.related_name[-1] == '+'
|
|
|
|
def get_related_field(self):
|
|
"""
|
|
Returns the field in the to' object to which this relationship is tied
|
|
(this is always the primary key on the target model). Provided for
|
|
symmetry with ManyToOneRel.
|
|
"""
|
|
return self.to._meta.pk
|
|
|
|
|
|
class ForeignObject(RelatedField):
|
|
requires_unique_target = True
|
|
generate_reverse_relation = True
|
|
related_accessor_class = ForeignRelatedObjectsDescriptor
|
|
|
|
def __init__(self, to, from_fields, to_fields, swappable=True, **kwargs):
|
|
self.from_fields = from_fields
|
|
self.to_fields = to_fields
|
|
self.swappable = swappable
|
|
|
|
if 'rel' not in kwargs:
|
|
kwargs['rel'] = ForeignObjectRel(
|
|
self, to,
|
|
related_name=kwargs.pop('related_name', None),
|
|
related_query_name=kwargs.pop('related_query_name', None),
|
|
limit_choices_to=kwargs.pop('limit_choices_to', None),
|
|
parent_link=kwargs.pop('parent_link', False),
|
|
on_delete=kwargs.pop('on_delete', CASCADE),
|
|
)
|
|
kwargs['verbose_name'] = kwargs.get('verbose_name', None)
|
|
|
|
super(ForeignObject, self).__init__(**kwargs)
|
|
|
|
def check(self, **kwargs):
|
|
errors = super(ForeignObject, self).check(**kwargs)
|
|
errors.extend(self._check_unique_target())
|
|
return errors
|
|
|
|
def _check_unique_target(self):
|
|
rel_is_string = isinstance(self.rel.to, six.string_types)
|
|
if rel_is_string or not self.requires_unique_target:
|
|
return []
|
|
|
|
# Skip if the
|
|
try:
|
|
self.foreign_related_fields
|
|
except FieldDoesNotExist:
|
|
return []
|
|
|
|
try:
|
|
self.related
|
|
except AttributeError:
|
|
return []
|
|
|
|
has_unique_field = any(rel_field.unique
|
|
for rel_field in self.foreign_related_fields)
|
|
if not has_unique_field and len(self.foreign_related_fields) > 1:
|
|
field_combination = ','.join(rel_field.name
|
|
for rel_field in self.foreign_related_fields)
|
|
model_name = self.rel.to.__name__
|
|
return [
|
|
checks.Error(
|
|
('No unique=True constraint '
|
|
'on field combination "%s" under model %s.') % (field_combination, model_name),
|
|
hint=('Set unique=True argument on any of the fields '
|
|
'"%s" under model %s.') % (field_combination, model_name),
|
|
obj=self,
|
|
id='E018',
|
|
)
|
|
]
|
|
elif not has_unique_field:
|
|
field_name = self.foreign_related_fields[0].name
|
|
model_name = self.rel.to.__name__
|
|
return [
|
|
checks.Error(
|
|
('%s.%s must have unique=True '
|
|
'because it is referenced by a foreign key.') % (model_name, field_name),
|
|
hint=None,
|
|
obj=self,
|
|
id='E019',
|
|
)
|
|
]
|
|
else:
|
|
return []
|
|
|
|
def deconstruct(self):
|
|
name, path, args, kwargs = super(ForeignObject, self).deconstruct()
|
|
kwargs['from_fields'] = self.from_fields
|
|
kwargs['to_fields'] = self.to_fields
|
|
# Work out string form of "to"
|
|
if isinstance(self.rel.to, six.string_types):
|
|
kwargs['to'] = self.rel.to
|
|
else:
|
|
kwargs['to'] = "%s.%s" % (self.rel.to._meta.app_label, self.rel.to._meta.object_name)
|
|
# If swappable is True, then see if we're actually pointing to the target
|
|
# of a swap.
|
|
swappable_setting = self.swappable_setting
|
|
if swappable_setting is not None:
|
|
# If it's already a settings reference, error
|
|
if hasattr(kwargs['to'], "setting_name"):
|
|
if kwargs['to'].setting_name != swappable_setting:
|
|
raise ValueError("Cannot deconstruct a ForeignKey pointing to a model that is swapped in place of more than one model (%s and %s)" % (kwargs['to'].setting_name, swappable_setting))
|
|
# Set it
|
|
from django.db.migrations.writer import SettingsReference
|
|
kwargs['to'] = SettingsReference(
|
|
kwargs['to'],
|
|
swappable_setting,
|
|
)
|
|
return name, path, args, kwargs
|
|
|
|
def resolve_related_fields(self):
|
|
if len(self.from_fields) < 1 or len(self.from_fields) != len(self.to_fields):
|
|
raise ValueError('Foreign Object from and to fields must be the same non-zero length')
|
|
if isinstance(self.rel.to, six.string_types):
|
|
raise ValueError('Related model %r cannot be resolved' % self.rel.to)
|
|
related_fields = []
|
|
for index in range(len(self.from_fields)):
|
|
from_field_name = self.from_fields[index]
|
|
to_field_name = self.to_fields[index]
|
|
from_field = (self if from_field_name == 'self'
|
|
else self.opts.get_field_by_name(from_field_name)[0])
|
|
to_field = (self.rel.to._meta.pk if to_field_name is None
|
|
else self.rel.to._meta.get_field_by_name(to_field_name)[0])
|
|
related_fields.append((from_field, to_field))
|
|
return related_fields
|
|
|
|
@property
|
|
def related_fields(self):
|
|
if not hasattr(self, '_related_fields'):
|
|
self._related_fields = self.resolve_related_fields()
|
|
return self._related_fields
|
|
|
|
@property
|
|
def reverse_related_fields(self):
|
|
return [(rhs_field, lhs_field) for lhs_field, rhs_field in self.related_fields]
|
|
|
|
@property
|
|
def local_related_fields(self):
|
|
return tuple(lhs_field for lhs_field, rhs_field in self.related_fields)
|
|
|
|
@property
|
|
def foreign_related_fields(self):
|
|
return tuple(rhs_field for lhs_field, rhs_field in self.related_fields)
|
|
|
|
def get_local_related_value(self, instance):
|
|
return self.get_instance_value_for_fields(instance, self.local_related_fields)
|
|
|
|
def get_foreign_related_value(self, instance):
|
|
return self.get_instance_value_for_fields(instance, self.foreign_related_fields)
|
|
|
|
@staticmethod
|
|
def get_instance_value_for_fields(instance, fields):
|
|
ret = []
|
|
for field in fields:
|
|
# Gotcha: in some cases (like fixture loading) a model can have
|
|
# different values in parent_ptr_id and parent's id. So, use
|
|
# instance.pk (that is, parent_ptr_id) when asked for instance.id.
|
|
opts = instance._meta
|
|
if field.primary_key:
|
|
possible_parent_link = opts.get_ancestor_link(field.model)
|
|
if not possible_parent_link or possible_parent_link.primary_key:
|
|
ret.append(instance.pk)
|
|
continue
|
|
ret.append(getattr(instance, field.attname))
|
|
return tuple(ret)
|
|
|
|
def get_attname_column(self):
|
|
attname, column = super(ForeignObject, self).get_attname_column()
|
|
return attname, None
|
|
|
|
def get_joining_columns(self, reverse_join=False):
|
|
source = self.reverse_related_fields if reverse_join else self.related_fields
|
|
return tuple((lhs_field.column, rhs_field.column) for lhs_field, rhs_field in source)
|
|
|
|
def get_reverse_joining_columns(self):
|
|
return self.get_joining_columns(reverse_join=True)
|
|
|
|
def get_extra_descriptor_filter(self, instance):
|
|
"""
|
|
Returns an extra filter condition for related object fetching when
|
|
user does 'instance.fieldname', that is the extra filter is used in
|
|
the descriptor of the field.
|
|
|
|
The filter should be either a dict usable in .filter(**kwargs) call or
|
|
a Q-object. The condition will be ANDed together with the relation's
|
|
joining columns.
|
|
|
|
A parallel method is get_extra_restriction() which is used in
|
|
JOIN and subquery conditions.
|
|
"""
|
|
return {}
|
|
|
|
def get_extra_restriction(self, where_class, alias, related_alias):
|
|
"""
|
|
Returns a pair condition used for joining and subquery pushdown. The
|
|
condition is something that responds to as_sql(qn, connection) method.
|
|
|
|
Note that currently referring both the 'alias' and 'related_alias'
|
|
will not work in some conditions, like subquery pushdown.
|
|
|
|
A parallel method is get_extra_descriptor_filter() which is used in
|
|
instance.fieldname related object fetching.
|
|
"""
|
|
return None
|
|
|
|
def get_path_info(self):
|
|
"""
|
|
Get path from this field to the related model.
|
|
"""
|
|
opts = self.rel.to._meta
|
|
from_opts = self.model._meta
|
|
return [PathInfo(from_opts, opts, self.foreign_related_fields, self, False, True)]
|
|
|
|
def get_reverse_path_info(self):
|
|
"""
|
|
Get path from the related model to this field's model.
|
|
"""
|
|
opts = self.model._meta
|
|
from_opts = self.rel.to._meta
|
|
pathinfos = [PathInfo(from_opts, opts, (opts.pk,), self.rel, not self.unique, False)]
|
|
return pathinfos
|
|
|
|
def get_lookup_constraint(self, constraint_class, alias, targets, sources, lookups,
|
|
raw_value):
|
|
from django.db.models.sql.where import SubqueryConstraint, AND, OR
|
|
root_constraint = constraint_class()
|
|
assert len(targets) == len(sources)
|
|
if len(lookups) > 1:
|
|
raise exceptions.FieldError('Relation fields do not support nested lookups')
|
|
lookup_type = lookups[0]
|
|
|
|
def get_normalized_value(value):
|
|
from django.db.models import Model
|
|
if isinstance(value, Model):
|
|
value_list = []
|
|
for source in sources:
|
|
# Account for one-to-one relations when sent a different model
|
|
while not isinstance(value, source.model) and source.rel:
|
|
source = source.rel.to._meta.get_field(source.rel.field_name)
|
|
value_list.append(getattr(value, source.attname))
|
|
return tuple(value_list)
|
|
elif not isinstance(value, tuple):
|
|
return (value,)
|
|
return value
|
|
|
|
is_multicolumn = len(self.related_fields) > 1
|
|
if (hasattr(raw_value, '_as_sql') or
|
|
hasattr(raw_value, 'get_compiler')):
|
|
root_constraint.add(SubqueryConstraint(alias, [target.column for target in targets],
|
|
[source.name for source in sources], raw_value),
|
|
AND)
|
|
elif lookup_type == 'isnull':
|
|
root_constraint.add(IsNull(Col(alias, targets[0], sources[0]), raw_value), AND)
|
|
elif (lookup_type == 'exact' or (lookup_type in ['gt', 'lt', 'gte', 'lte']
|
|
and not is_multicolumn)):
|
|
value = get_normalized_value(raw_value)
|
|
for target, source, val in zip(targets, sources, value):
|
|
lookup_class = target.get_lookup(lookup_type)
|
|
root_constraint.add(
|
|
lookup_class(Col(alias, target, source), val), AND)
|
|
elif lookup_type in ['range', 'in'] and not is_multicolumn:
|
|
values = [get_normalized_value(value) for value in raw_value]
|
|
value = [val[0] for val in values]
|
|
lookup_class = targets[0].get_lookup(lookup_type)
|
|
root_constraint.add(lookup_class(Col(alias, targets[0], sources[0]), value), AND)
|
|
elif lookup_type == 'in':
|
|
values = [get_normalized_value(value) for value in raw_value]
|
|
for value in values:
|
|
value_constraint = constraint_class()
|
|
for source, target, val in zip(sources, targets, value):
|
|
lookup_class = target.get_lookup('exact')
|
|
lookup = lookup_class(Col(alias, target, source), val)
|
|
value_constraint.add(lookup, AND)
|
|
root_constraint.add(value_constraint, OR)
|
|
else:
|
|
raise TypeError('Related Field got invalid lookup: %s' % lookup_type)
|
|
return root_constraint
|
|
|
|
@property
|
|
def attnames(self):
|
|
return tuple(field.attname for field in self.local_related_fields)
|
|
|
|
def get_defaults(self):
|
|
return tuple(field.get_default() for field in self.local_related_fields)
|
|
|
|
def contribute_to_class(self, cls, name, virtual_only=False):
|
|
super(ForeignObject, self).contribute_to_class(cls, name, virtual_only=virtual_only)
|
|
setattr(cls, self.name, ReverseSingleRelatedObjectDescriptor(self))
|
|
|
|
def contribute_to_related_class(self, cls, related):
|
|
# Internal FK's - i.e., those with a related name ending with '+' -
|
|
# and swapped models don't get a related descriptor.
|
|
if not self.rel.is_hidden() and not related.model._meta.swapped:
|
|
setattr(cls, related.get_accessor_name(), self.related_accessor_class(related))
|
|
if self.rel.limit_choices_to:
|
|
cls._meta.related_fkey_lookups.append(self.rel.limit_choices_to)
|
|
|
|
|
|
class ForeignKey(ForeignObject):
|
|
empty_strings_allowed = False
|
|
default_error_messages = {
|
|
'invalid': _('%(model)s instance with pk %(pk)r does not exist.')
|
|
}
|
|
description = _("Foreign Key (type determined by related field)")
|
|
|
|
def __init__(self, to, to_field=None, rel_class=ManyToOneRel,
|
|
db_constraint=True, **kwargs):
|
|
try:
|
|
to._meta.model_name
|
|
except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
|
|
assert isinstance(to, six.string_types), "%s(%r) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string %r" % (self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT)
|
|
else:
|
|
# For backwards compatibility purposes, we need to *try* and set
|
|
# the to_field during FK construction. It won't be guaranteed to
|
|
# be correct until contribute_to_class is called. Refs #12190.
|
|
to_field = to_field or (to._meta.pk and to._meta.pk.name)
|
|
|
|
if 'db_index' not in kwargs:
|
|
kwargs['db_index'] = True
|
|
|
|
self.db_constraint = db_constraint
|
|
|
|
kwargs['rel'] = rel_class(
|
|
self, to, to_field,
|
|
related_name=kwargs.pop('related_name', None),
|
|
related_query_name=kwargs.pop('related_query_name', None),
|
|
limit_choices_to=kwargs.pop('limit_choices_to', None),
|
|
parent_link=kwargs.pop('parent_link', False),
|
|
on_delete=kwargs.pop('on_delete', CASCADE),
|
|
)
|
|
super(ForeignKey, self).__init__(to, ['self'], [to_field], **kwargs)
|
|
|
|
def check(self, **kwargs):
|
|
errors = super(ForeignKey, self).check(**kwargs)
|
|
errors.extend(self._check_on_delete())
|
|
return errors
|
|
|
|
def _check_on_delete(self):
|
|
on_delete = getattr(self.rel, 'on_delete', None)
|
|
if on_delete == SET_NULL and not self.null:
|
|
return [
|
|
checks.Error(
|
|
'The field specifies on_delete=SET_NULL, but cannot be null.',
|
|
hint='Set null=True argument on the field.',
|
|
obj=self,
|
|
id='E020',
|
|
)
|
|
]
|
|
elif on_delete == SET_DEFAULT and not self.has_default():
|
|
return [
|
|
checks.Error(
|
|
'The field specifies on_delete=SET_DEFAULT, but has no default value.',
|
|
hint=None,
|
|
obj=self,
|
|
id='E021',
|
|
)
|
|
]
|
|
else:
|
|
return []
|
|
|
|
def deconstruct(self):
|
|
name, path, args, kwargs = super(ForeignKey, self).deconstruct()
|
|
del kwargs['to_fields']
|
|
del kwargs['from_fields']
|
|
# Handle the simpler arguments
|
|
if self.db_index:
|
|
del kwargs['db_index']
|
|
else:
|
|
kwargs['db_index'] = False
|
|
if self.db_constraint is not True:
|
|
kwargs['db_constraint'] = self.db_constraint
|
|
if self.rel.on_delete is not CASCADE:
|
|
kwargs['on_delete'] = self.rel.on_delete
|
|
# Rel needs more work.
|
|
if self.rel.field_name:
|
|
kwargs['to_field'] = self.rel.field_name
|
|
return name, path, args, kwargs
|
|
|
|
@property
|
|
def related_field(self):
|
|
return self.foreign_related_fields[0]
|
|
|
|
def get_reverse_path_info(self):
|
|
"""
|
|
Get path from the related model to this field's model.
|
|
"""
|
|
opts = self.model._meta
|
|
from_opts = self.rel.to._meta
|
|
pathinfos = [PathInfo(from_opts, opts, (opts.pk,), self.rel, not self.unique, False)]
|
|
return pathinfos
|
|
|
|
def validate(self, value, model_instance):
|
|
if self.rel.parent_link:
|
|
return
|
|
super(ForeignKey, self).validate(value, model_instance)
|
|
if value is None:
|
|
return
|
|
|
|
using = router.db_for_read(model_instance.__class__, instance=model_instance)
|
|
qs = self.rel.to._default_manager.using(using).filter(
|
|
**{self.rel.field_name: value}
|
|
)
|
|
qs = qs.complex_filter(self.rel.limit_choices_to)
|
|
if not qs.exists():
|
|
raise exceptions.ValidationError(
|
|
self.error_messages['invalid'],
|
|
code='invalid',
|
|
params={'model': self.rel.to._meta.verbose_name, 'pk': value},
|
|
)
|
|
|
|
def get_attname(self):
|
|
return '%s_id' % self.name
|
|
|
|
def get_attname_column(self):
|
|
attname = self.get_attname()
|
|
column = self.db_column or attname
|
|
return attname, column
|
|
|
|
def get_validator_unique_lookup_type(self):
|
|
return '%s__%s__exact' % (self.name, self.related_field.name)
|
|
|
|
def get_default(self):
|
|
"Here we check if the default value is an object and return the to_field if so."
|
|
field_default = super(ForeignKey, self).get_default()
|
|
if isinstance(field_default, self.rel.to):
|
|
return getattr(field_default, self.related_field.attname)
|
|
return field_default
|
|
|
|
def get_db_prep_save(self, value, connection):
|
|
if value == '' or value is None:
|
|
return None
|
|
else:
|
|
return self.related_field.get_db_prep_save(value,
|
|
connection=connection)
|
|
|
|
def value_to_string(self, obj):
|
|
if not obj:
|
|
# In required many-to-one fields with only one available choice,
|
|
# select that one available choice. Note: For SelectFields
|
|
# we have to check that the length of choices is *2*, not 1,
|
|
# because SelectFields always have an initial "blank" value.
|
|
if not self.blank and self.choices:
|
|
choice_list = self.get_choices_default()
|
|
if len(choice_list) == 2:
|
|
return smart_text(choice_list[1][0])
|
|
return super(ForeignKey, self).value_to_string(obj)
|
|
|
|
def contribute_to_related_class(self, cls, related):
|
|
super(ForeignKey, self).contribute_to_related_class(cls, related)
|
|
if self.rel.field_name is None:
|
|
self.rel.field_name = cls._meta.pk.name
|
|
|
|
def formfield(self, **kwargs):
|
|
db = kwargs.pop('using', None)
|
|
if isinstance(self.rel.to, six.string_types):
|
|
raise ValueError("Cannot create form field for %r yet, because "
|
|
"its related model %r has not been loaded yet" %
|
|
(self.name, self.rel.to))
|
|
defaults = {
|
|
'form_class': forms.ModelChoiceField,
|
|
'queryset': self.rel.to._default_manager.using(db).complex_filter(self.rel.limit_choices_to),
|
|
'to_field_name': self.rel.field_name,
|
|
}
|
|
defaults.update(kwargs)
|
|
return super(ForeignKey, self).formfield(**defaults)
|
|
|
|
def db_type(self, connection):
|
|
# The database column type of a ForeignKey is the column type
|
|
# of the field to which it points. An exception is if the ForeignKey
|
|
# points to an AutoField/PositiveIntegerField/PositiveSmallIntegerField,
|
|
# in which case the column type is simply that of an IntegerField.
|
|
# If the database needs similar types for key fields however, the only
|
|
# thing we can do is making AutoField an IntegerField.
|
|
rel_field = self.related_field
|
|
if (isinstance(rel_field, AutoField) or
|
|
(not connection.features.related_fields_match_type and
|
|
isinstance(rel_field, (PositiveIntegerField,
|
|
PositiveSmallIntegerField)))):
|
|
return IntegerField().db_type(connection=connection)
|
|
return rel_field.db_type(connection=connection)
|
|
|
|
def db_parameters(self, connection):
|
|
return {"type": self.db_type(connection), "check": []}
|
|
|
|
|
|
class OneToOneField(ForeignKey):
|
|
"""
|
|
A OneToOneField is essentially the same as a ForeignKey, with the exception
|
|
that always carries a "unique" constraint with it and the reverse relation
|
|
always returns the object pointed to (since there will only ever be one),
|
|
rather than returning a list.
|
|
"""
|
|
related_accessor_class = SingleRelatedObjectDescriptor
|
|
description = _("One-to-one relationship")
|
|
|
|
def __init__(self, to, to_field=None, **kwargs):
|
|
kwargs['unique'] = True
|
|
super(OneToOneField, self).__init__(to, to_field, OneToOneRel, **kwargs)
|
|
|
|
def deconstruct(self):
|
|
name, path, args, kwargs = super(OneToOneField, self).deconstruct()
|
|
if "unique" in kwargs:
|
|
del kwargs['unique']
|
|
return name, path, args, kwargs
|
|
|
|
def formfield(self, **kwargs):
|
|
if self.rel.parent_link:
|
|
return None
|
|
return super(OneToOneField, self).formfield(**kwargs)
|
|
|
|
def save_form_data(self, instance, data):
|
|
if isinstance(data, self.rel.to):
|
|
setattr(instance, self.name, data)
|
|
else:
|
|
setattr(instance, self.attname, data)
|
|
|
|
|
|
def create_many_to_many_intermediary_model(field, klass):
|
|
from django.db import models
|
|
managed = True
|
|
if isinstance(field.rel.to, six.string_types) and field.rel.to != RECURSIVE_RELATIONSHIP_CONSTANT:
|
|
to_model = field.rel.to
|
|
to = to_model.split('.')[-1]
|
|
|
|
def set_managed(field, model, cls):
|
|
field.rel.through._meta.managed = model._meta.managed or cls._meta.managed
|
|
add_lazy_relation(klass, field, to_model, set_managed)
|
|
elif isinstance(field.rel.to, six.string_types):
|
|
to = klass._meta.object_name
|
|
to_model = klass
|
|
managed = klass._meta.managed
|
|
else:
|
|
to = field.rel.to._meta.object_name
|
|
to_model = field.rel.to
|
|
managed = klass._meta.managed or to_model._meta.managed
|
|
name = '%s_%s' % (klass._meta.object_name, field.name)
|
|
if field.rel.to == RECURSIVE_RELATIONSHIP_CONSTANT or to == klass._meta.object_name:
|
|
from_ = 'from_%s' % to.lower()
|
|
to = 'to_%s' % to.lower()
|
|
else:
|
|
from_ = klass._meta.model_name
|
|
to = to.lower()
|
|
meta = type('Meta', (object,), {
|
|
'db_table': field._get_m2m_db_table(klass._meta),
|
|
'managed': managed,
|
|
'auto_created': klass,
|
|
'app_label': klass._meta.app_label,
|
|
'db_tablespace': klass._meta.db_tablespace,
|
|
'unique_together': (from_, to),
|
|
'verbose_name': '%(from)s-%(to)s relationship' % {'from': from_, 'to': to},
|
|
'verbose_name_plural': '%(from)s-%(to)s relationships' % {'from': from_, 'to': to},
|
|
'apps': field.model._meta.apps,
|
|
})
|
|
# Construct and return the new class.
|
|
return type(str(name), (models.Model,), {
|
|
'Meta': meta,
|
|
'__module__': klass.__module__,
|
|
from_: models.ForeignKey(klass, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.rel.db_constraint),
|
|
to: models.ForeignKey(to_model, related_name='%s+' % name, db_tablespace=field.db_tablespace, db_constraint=field.rel.db_constraint)
|
|
})
|
|
|
|
|
|
class ManyToManyField(RelatedField):
|
|
description = _("Many-to-many relationship")
|
|
|
|
def __init__(self, to, db_constraint=True, swappable=True, **kwargs):
|
|
try:
|
|
to._meta
|
|
except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
|
|
assert isinstance(to, six.string_types), "%s(%r) is invalid. First parameter to ManyToManyField must be either a model, a model name, or the string %r" % (self.__class__.__name__, to, RECURSIVE_RELATIONSHIP_CONSTANT)
|
|
# Class names must be ASCII in Python 2.x, so we forcibly coerce it here to break early if there's a problem.
|
|
to = str(to)
|
|
|
|
kwargs['verbose_name'] = kwargs.get('verbose_name', None)
|
|
kwargs['rel'] = ManyToManyRel(to,
|
|
related_name=kwargs.pop('related_name', None),
|
|
related_query_name=kwargs.pop('related_query_name', None),
|
|
limit_choices_to=kwargs.pop('limit_choices_to', None),
|
|
symmetrical=kwargs.pop('symmetrical', to == RECURSIVE_RELATIONSHIP_CONSTANT),
|
|
through=kwargs.pop('through', None),
|
|
db_constraint=db_constraint,
|
|
)
|
|
|
|
self.swappable = swappable
|
|
self.db_table = kwargs.pop('db_table', None)
|
|
if kwargs['rel'].through is not None:
|
|
assert self.db_table is None, "Cannot specify a db_table if an intermediary model is used."
|
|
|
|
super(ManyToManyField, self).__init__(**kwargs)
|
|
|
|
def check(self, **kwargs):
|
|
errors = super(ManyToManyField, self).check(**kwargs)
|
|
errors.extend(self._check_unique(**kwargs))
|
|
errors.extend(self._check_relationship_model(**kwargs))
|
|
return errors
|
|
|
|
def _check_unique(self, **kwargs):
|
|
if self.unique:
|
|
return [
|
|
checks.Error(
|
|
'ManyToManyFields must not be unique.',
|
|
hint=None,
|
|
obj=self,
|
|
id='E022',
|
|
)
|
|
]
|
|
return []
|
|
|
|
def _check_relationship_model(self, from_model=None, **kwargs):
|
|
errors = []
|
|
|
|
if self.rel.through not in apps.get_models(include_auto_created=True):
|
|
# The relationship model is not installed.
|
|
errors.append(
|
|
checks.Error(
|
|
('The field specifies a many-to-many relation through model '
|
|
'%s, which has not been installed.') % self.rel.through,
|
|
hint=('Ensure that you did not misspell the model name and '
|
|
'the model is not abstract. Does your INSTALLED_APPS '
|
|
'setting contain the app where %s is defined?') % self.rel.through,
|
|
obj=self,
|
|
id='E023',
|
|
)
|
|
)
|
|
|
|
elif not isinstance(self.rel.through, six.string_types):
|
|
|
|
assert from_model is not None, \
|
|
"ManyToManyField with intermediate " \
|
|
"tables cannot be checked if you don't pass the model " \
|
|
"where the field is attached to."
|
|
|
|
# Set some useful local variables
|
|
to_model = self.rel.to
|
|
from_model_name = from_model._meta.object_name
|
|
if isinstance(to_model, six.string_types):
|
|
to_model_name = to_model
|
|
else:
|
|
to_model_name = to_model._meta.object_name
|
|
relationship_model_name = self.rel.through._meta.object_name
|
|
self_referential = from_model == to_model
|
|
|
|
# Check symmetrical attribute.
|
|
if (self_referential and self.rel.symmetrical and
|
|
not self.rel.through._meta.auto_created):
|
|
errors.append(
|
|
checks.Error(
|
|
'Many-to-many fields with intermediate tables must not be symmetrical.',
|
|
hint=None,
|
|
obj=self,
|
|
id='E024',
|
|
)
|
|
)
|
|
|
|
# Count foreign keys in intermediate model
|
|
if self_referential:
|
|
seen_self = sum(from_model == getattr(field.rel, 'to', None)
|
|
for field in self.rel.through._meta.fields)
|
|
|
|
if seen_self > 2:
|
|
errors.append(
|
|
checks.Error(
|
|
('The model is used as an intermediary model by '
|
|
'%s, but it has more than two foreign keys '
|
|
'to %s, which is ambiguous and is not permitted.') % (self, from_model_name),
|
|
hint=None,
|
|
obj=self.rel.through,
|
|
id='E025',
|
|
)
|
|
)
|
|
|
|
else:
|
|
# Count foreign keys in relationship model
|
|
seen_from = sum(from_model == getattr(field.rel, 'to', None)
|
|
for field in self.rel.through._meta.fields)
|
|
seen_to = sum(to_model == getattr(field.rel, 'to', None)
|
|
for field in self.rel.through._meta.fields)
|
|
|
|
if seen_from > 1:
|
|
errors.append(
|
|
checks.Error(
|
|
('The model is used as an intermediary model by '
|
|
'%s, but it has more than one foreign key '
|
|
'to %s, which is ambiguous and is not permitted.') % (self, from_model_name),
|
|
hint=('If you want to create a recursive relationship, '
|
|
'use ForeignKey("self", symmetrical=False, '
|
|
'through="%s").') % relationship_model_name,
|
|
obj=self,
|
|
id='E026',
|
|
)
|
|
)
|
|
|
|
if seen_to > 1:
|
|
errors.append(
|
|
checks.Error(
|
|
('The model is used as an intermediary model by '
|
|
'%s, but it has more than one foreign key '
|
|
'to %s, which is ambiguous and is not permitted.') % (self, to_model_name),
|
|
hint=('If you want to create a recursive '
|
|
'relationship, use ForeignKey("self", '
|
|
'symmetrical=False, through="%s").') % relationship_model_name,
|
|
obj=self,
|
|
id='E027',
|
|
)
|
|
)
|
|
|
|
if seen_from == 0 or seen_to == 0:
|
|
errors.append(
|
|
checks.Error(
|
|
('The model is used as an intermediary model by '
|
|
'%s, but it misses a foreign key to %s or %s.') % (
|
|
self, from_model_name, to_model_name
|
|
),
|
|
hint=None,
|
|
obj=self.rel.through,
|
|
id='E028',
|
|
)
|
|
)
|
|
return errors
|
|
|
|
def deconstruct(self):
|
|
name, path, args, kwargs = super(ManyToManyField, self).deconstruct()
|
|
# Handle the simpler arguments
|
|
if self.rel.db_constraint is not True:
|
|
kwargs['db_constraint'] = self.rel.db_constraint
|
|
if "help_text" in kwargs:
|
|
del kwargs['help_text']
|
|
# Rel needs more work.
|
|
if isinstance(self.rel.to, six.string_types):
|
|
kwargs['to'] = self.rel.to
|
|
else:
|
|
kwargs['to'] = "%s.%s" % (self.rel.to._meta.app_label, self.rel.to._meta.object_name)
|
|
# If swappable is True, then see if we're actually pointing to the target
|
|
# of a swap.
|
|
swappable_setting = self.swappable_setting
|
|
if swappable_setting is not None:
|
|
# If it's already a settings reference, error
|
|
if hasattr(kwargs['to'], "setting_name"):
|
|
if kwargs['to'].setting_name != swappable_setting:
|
|
raise ValueError("Cannot deconstruct a ManyToManyField pointing to a model that is swapped in place of more than one model (%s and %s)" % (kwargs['to'].setting_name, swappable_setting))
|
|
# Set it
|
|
from django.db.migrations.writer import SettingsReference
|
|
kwargs['to'] = SettingsReference(
|
|
kwargs['to'],
|
|
swappable_setting,
|
|
)
|
|
return name, path, args, kwargs
|
|
|
|
def _get_path_info(self, direct=False):
|
|
"""
|
|
Called by both direct an indirect m2m traversal.
|
|
"""
|
|
pathinfos = []
|
|
int_model = self.rel.through
|
|
linkfield1 = int_model._meta.get_field_by_name(self.m2m_field_name())[0]
|
|
linkfield2 = int_model._meta.get_field_by_name(self.m2m_reverse_field_name())[0]
|
|
if direct:
|
|
join1infos = linkfield1.get_reverse_path_info()
|
|
join2infos = linkfield2.get_path_info()
|
|
else:
|
|
join1infos = linkfield2.get_reverse_path_info()
|
|
join2infos = linkfield1.get_path_info()
|
|
pathinfos.extend(join1infos)
|
|
pathinfos.extend(join2infos)
|
|
return pathinfos
|
|
|
|
def get_path_info(self):
|
|
return self._get_path_info(direct=True)
|
|
|
|
def get_reverse_path_info(self):
|
|
return self._get_path_info(direct=False)
|
|
|
|
def get_choices_default(self):
|
|
return Field.get_choices(self, include_blank=False)
|
|
|
|
def _get_m2m_db_table(self, opts):
|
|
"Function that can be curried to provide the m2m table name for this relation"
|
|
if self.rel.through is not None:
|
|
return self.rel.through._meta.db_table
|
|
elif self.db_table:
|
|
return self.db_table
|
|
else:
|
|
return utils.truncate_name('%s_%s' % (opts.db_table, self.name),
|
|
connection.ops.max_name_length())
|
|
|
|
def _get_m2m_attr(self, related, attr):
|
|
"Function that can be curried to provide the source accessor or DB column name for the m2m table"
|
|
cache_attr = '_m2m_%s_cache' % attr
|
|
if hasattr(self, cache_attr):
|
|
return getattr(self, cache_attr)
|
|
for f in self.rel.through._meta.fields:
|
|
if hasattr(f, 'rel') and f.rel and f.rel.to == related.model:
|
|
setattr(self, cache_attr, getattr(f, attr))
|
|
return getattr(self, cache_attr)
|
|
|
|
def _get_m2m_reverse_attr(self, related, attr):
|
|
"Function that can be curried to provide the related accessor or DB column name for the m2m table"
|
|
cache_attr = '_m2m_reverse_%s_cache' % attr
|
|
if hasattr(self, cache_attr):
|
|
return getattr(self, cache_attr)
|
|
found = False
|
|
for f in self.rel.through._meta.fields:
|
|
if hasattr(f, 'rel') and f.rel and f.rel.to == related.parent_model:
|
|
if related.model == related.parent_model:
|
|
# If this is an m2m-intermediate to self,
|
|
# the first foreign key you find will be
|
|
# the source column. Keep searching for
|
|
# the second foreign key.
|
|
if found:
|
|
setattr(self, cache_attr, getattr(f, attr))
|
|
break
|
|
else:
|
|
found = True
|
|
else:
|
|
setattr(self, cache_attr, getattr(f, attr))
|
|
break
|
|
return getattr(self, cache_attr)
|
|
|
|
def value_to_string(self, obj):
|
|
data = ''
|
|
if obj:
|
|
qs = getattr(obj, self.name).all()
|
|
data = [instance._get_pk_val() for instance in qs]
|
|
else:
|
|
# In required many-to-many fields with only one available choice,
|
|
# select that one available choice.
|
|
if not self.blank:
|
|
choices_list = self.get_choices_default()
|
|
if len(choices_list) == 1:
|
|
data = [choices_list[0][0]]
|
|
return smart_text(data)
|
|
|
|
def contribute_to_class(self, cls, name):
|
|
# To support multiple relations to self, it's useful to have a non-None
|
|
# related name on symmetrical relations for internal reasons. The
|
|
# concept doesn't make a lot of sense externally ("you want me to
|
|
# specify *what* on my non-reversible relation?!"), so we set it up
|
|
# automatically. The funky name reduces the chance of an accidental
|
|
# clash.
|
|
if self.rel.symmetrical and (self.rel.to == "self" or self.rel.to == cls._meta.object_name):
|
|
self.rel.related_name = "%s_rel_+" % name
|
|
|
|
super(ManyToManyField, self).contribute_to_class(cls, name)
|
|
|
|
# The intermediate m2m model is not auto created if:
|
|
# 1) There is a manually specified intermediate, or
|
|
# 2) The class owning the m2m field is abstract.
|
|
# 3) The class owning the m2m field has been swapped out.
|
|
if not self.rel.through and not cls._meta.abstract and not cls._meta.swapped:
|
|
self.rel.through = create_many_to_many_intermediary_model(self, cls)
|
|
|
|
# Add the descriptor for the m2m relation
|
|
setattr(cls, self.name, ReverseManyRelatedObjectsDescriptor(self))
|
|
|
|
# Set up the accessor for the m2m table name for the relation
|
|
self.m2m_db_table = curry(self._get_m2m_db_table, cls._meta)
|
|
|
|
# Populate some necessary rel arguments so that cross-app relations
|
|
# work correctly.
|
|
if isinstance(self.rel.through, six.string_types):
|
|
def resolve_through_model(field, model, cls):
|
|
field.rel.through = model
|
|
add_lazy_relation(cls, self, self.rel.through, resolve_through_model)
|
|
|
|
def contribute_to_related_class(self, cls, related):
|
|
# Internal M2Ms (i.e., those with a related name ending with '+')
|
|
# and swapped models don't get a related descriptor.
|
|
if not self.rel.is_hidden() and not related.model._meta.swapped:
|
|
setattr(cls, related.get_accessor_name(), ManyRelatedObjectsDescriptor(related))
|
|
|
|
# Set up the accessors for the column names on the m2m table
|
|
self.m2m_column_name = curry(self._get_m2m_attr, related, 'column')
|
|
self.m2m_reverse_name = curry(self._get_m2m_reverse_attr, related, 'column')
|
|
|
|
self.m2m_field_name = curry(self._get_m2m_attr, related, 'name')
|
|
self.m2m_reverse_field_name = curry(self._get_m2m_reverse_attr, related, 'name')
|
|
|
|
get_m2m_rel = curry(self._get_m2m_attr, related, 'rel')
|
|
self.m2m_target_field_name = lambda: get_m2m_rel().field_name
|
|
get_m2m_reverse_rel = curry(self._get_m2m_reverse_attr, related, 'rel')
|
|
self.m2m_reverse_target_field_name = lambda: get_m2m_reverse_rel().field_name
|
|
|
|
def set_attributes_from_rel(self):
|
|
pass
|
|
|
|
def value_from_object(self, obj):
|
|
"Returns the value of this field in the given model instance."
|
|
return getattr(obj, self.attname).all()
|
|
|
|
def save_form_data(self, instance, data):
|
|
setattr(instance, self.attname, data)
|
|
|
|
def formfield(self, **kwargs):
|
|
db = kwargs.pop('using', None)
|
|
defaults = {
|
|
'form_class': forms.ModelMultipleChoiceField,
|
|
'queryset': self.rel.to._default_manager.using(db).complex_filter(self.rel.limit_choices_to)
|
|
}
|
|
defaults.update(kwargs)
|
|
# If initial is passed in, it's a list of related objects, but the
|
|
# MultipleChoiceField takes a list of IDs.
|
|
if defaults.get('initial') is not None:
|
|
initial = defaults['initial']
|
|
if callable(initial):
|
|
initial = initial()
|
|
defaults['initial'] = [i._get_pk_val() for i in initial]
|
|
return super(ManyToManyField, self).formfield(**defaults)
|
|
|
|
def db_type(self, connection):
|
|
# A ManyToManyField is not represented by a single column,
|
|
# so return None.
|
|
return None
|
|
|
|
def db_parameters(self, connection):
|
|
return {"type": None, "check": None}
|