--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/web/lib/django/db/models/fields/related.py Wed Jan 20 00:34:04 2010 +0100
@@ -0,0 +1,984 @@
+from django.db import connection, transaction
+from django.db.backends import util
+from django.db.models import signals, get_model
+from django.db.models.fields import AutoField, Field, IntegerField, PositiveIntegerField, PositiveSmallIntegerField, FieldDoesNotExist
+from django.db.models.related import RelatedObject
+from django.db.models.query import QuerySet
+from django.db.models.query_utils import QueryWrapper
+from django.utils.encoding import smart_unicode
+from django.utils.translation import ugettext_lazy, string_concat, ungettext, ugettext as _
+from django.utils.functional import curry
+from django.core import exceptions
+from django import forms
+
+try:
+ set
+except NameError:
+ from sets import Set as set # Python 2.3 fallback
+
+RECURSIVE_RELATIONSHIP_CONSTANT = 'self'
+
+pending_lookups = {}
+
+def add_lazy_relation(cls, field, relation, operation):
+ """
+ Adds a lookup on ``cls`` when a related field is defined using a string,
+ i.e.::
+
+ class MyModel(Model):
+ fk = ForeignKey("AnotherModel")
+
+ This string can be:
+
+ * RECURSIVE_RELATIONSHIP_CONSTANT (i.e. "self") to indicate a recursive
+ relation.
+
+ * The name of a model (i.e "AnotherModel") to indicate another model in
+ the same app.
+
+ * An app-label and model name (i.e. "someapp.AnotherModel") to indicate
+ another model in a different app.
+
+ If the other model hasn't yet been loaded -- almost a given if you're using
+ lazy relationships -- then the relation won't be set up until the
+ class_prepared signal fires at the end of model initialization.
+
+ operation is the work that must be performed once the relation can be resolved.
+ """
+ # Check for recursive relations
+ if relation == RECURSIVE_RELATIONSHIP_CONSTANT:
+ app_label = cls._meta.app_label
+ model_name = cls.__name__
+
+ else:
+ # Look for an "app.Model" relation
+ try:
+ app_label, model_name = relation.split(".")
+ except ValueError:
+ # If we can't split, assume a model in current app
+ app_label = cls._meta.app_label
+ model_name = relation
+
+ # Try to look up the related model, and if it's already loaded resolve the
+ # string right away. If get_model returns None, it means that the related
+ # model isn't loaded yet, so we need to pend the relation until the class
+ # is prepared.
+ model = get_model(app_label, model_name, False)
+ if model:
+ operation(field, model, cls)
+ else:
+ key = (app_label, model_name)
+ value = (cls, field, operation)
+ pending_lookups.setdefault(key, []).append(value)
+
+def do_pending_lookups(sender, **kwargs):
+ """
+ Handle any pending relations to the sending model. Sent from class_prepared.
+ """
+ key = (sender._meta.app_label, sender.__name__)
+ for cls, field, operation in pending_lookups.pop(key, []):
+ operation(field, sender, cls)
+
+signals.class_prepared.connect(do_pending_lookups)
+
+#HACK
+class RelatedField(object):
+ def contribute_to_class(self, cls, name):
+ sup = super(RelatedField, self)
+
+ # Add an accessor to allow easy determination of the related query path for this field
+ self.related_query_name = curry(self._get_related_query_name, cls._meta)
+
+ if hasattr(sup, 'contribute_to_class'):
+ sup.contribute_to_class(cls, name)
+
+ if not cls._meta.abstract and self.rel.related_name:
+ self.rel.related_name = self.rel.related_name % {'class': cls.__name__.lower()}
+
+ other = self.rel.to
+ if isinstance(other, basestring):
+ def resolve_related_class(field, model, cls):
+ field.rel.to = model
+ field.do_related_class(model, cls)
+ add_lazy_relation(cls, self, other, resolve_related_class)
+ else:
+ self.do_related_class(other, cls)
+
+ def set_attributes_from_rel(self):
+ self.name = self.name or (self.rel.to._meta.object_name.lower() + '_' + self.rel.to._meta.pk.name)
+ if self.verbose_name is None:
+ self.verbose_name = self.rel.to._meta.verbose_name
+ self.rel.field_name = self.rel.field_name or self.rel.to._meta.pk.name
+
+ def do_related_class(self, other, cls):
+ self.set_attributes_from_rel()
+ self.related = RelatedObject(other, cls, self)
+ if not cls._meta.abstract:
+ self.contribute_to_related_class(other, self.related)
+
+ def get_db_prep_lookup(self, lookup_type, value):
+ # If we are doing a lookup on a Related Field, we must be
+ # comparing object instances. The value should be the PK of value,
+ # not value itself.
+ def pk_trace(value):
+ # Value may be a primary key, or an object held in a relation.
+ # If it is an object, then we need to get the primary key value for
+ # that object. In certain conditions (especially one-to-one relations),
+ # the primary key may itself be an object - so we need to keep drilling
+ # down until we hit a value that can be used for a comparison.
+ v, field = value, None
+ try:
+ while True:
+ v, field = getattr(v, v._meta.pk.name), v._meta.pk
+ except AttributeError:
+ pass
+
+ if field:
+ if lookup_type in ('range', 'in'):
+ v = [v]
+ v = field.get_db_prep_lookup(lookup_type, v)
+ if isinstance(v, list):
+ v = v[0]
+ return v
+
+ if hasattr(value, 'as_sql') or hasattr(value, '_as_sql'):
+ # If the value has a relabel_aliases method, it will need to
+ # be invoked before the final SQL is evaluated
+ if hasattr(value, 'relabel_aliases'):
+ return value
+ if hasattr(value, 'as_sql'):
+ sql, params = value.as_sql()
+ else:
+ sql, params = value._as_sql()
+ return QueryWrapper(('(%s)' % sql), params)
+
+ # FIXME: lt and gt are explicitally allowed to make
+ # get_(next/prev)_by_date work; other lookups are not allowed since that
+ # gets messy pretty quick. This is a good candidate for some refactoring
+ # in the future.
+ if lookup_type in ['exact', 'gt', 'lt', 'gte', 'lte']:
+ return [pk_trace(value)]
+ if lookup_type in ('range', 'in'):
+ return [pk_trace(v) for v in value]
+ elif lookup_type == 'isnull':
+ return []
+ raise TypeError, "Related Field has invalid lookup: %s" % lookup_type
+
+ def _get_related_query_name(self, opts):
+ # This method defines the name that can be used to identify this
+ # related object in a table-spanning query. It uses the lower-cased
+ # object_name by default, but this can be overridden with the
+ # "related_name" option.
+ return self.rel.related_name or opts.object_name.lower()
+
+class SingleRelatedObjectDescriptor(object):
+ # This class provides the functionality that makes the related-object
+ # managers available as attributes on a model class, for fields that have
+ # a single "remote" value, on the class pointed to by a related field.
+ # In the example "place.restaurant", the restaurant attribute is a
+ # SingleRelatedObjectDescriptor instance.
+ def __init__(self, related):
+ self.related = related
+ self.cache_name = '_%s_cache' % related.get_accessor_name()
+
+ def __get__(self, instance, instance_type=None):
+ if instance is None:
+ return self
+ try:
+ return getattr(instance, self.cache_name)
+ except AttributeError:
+ params = {'%s__pk' % self.related.field.name: instance._get_pk_val()}
+ rel_obj = self.related.model._base_manager.get(**params)
+ setattr(instance, self.cache_name, rel_obj)
+ return rel_obj
+
+ def __set__(self, instance, value):
+ if instance is None:
+ raise AttributeError, "%s must be accessed via instance" % self.related.opts.object_name
+
+ # The similarity of the code below to the code in
+ # ReverseSingleRelatedObjectDescriptor is annoying, but there's a bunch
+ # of small differences that would make a common base class convoluted.
+
+ # 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.related.field.null == False:
+ raise ValueError('Cannot assign None: "%s.%s" does not allow null values.' %
+ (instance._meta.object_name, self.related.get_accessor_name()))
+ elif value is not None and not isinstance(value, self.related.model):
+ raise ValueError('Cannot assign "%r": "%s.%s" must be a "%s" instance.' %
+ (value, instance._meta.object_name,
+ self.related.get_accessor_name(), self.related.opts.object_name))
+
+ # Set the value of the related field to the value of the related object's related field
+ setattr(value, self.related.field.attname, getattr(instance, self.related.field.rel.get_related_field().attname))
+
+ # 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)
+ setattr(value, self.related.field.get_cache_name(), instance)
+
+class ReverseSingleRelatedObjectDescriptor(object):
+ # This class provides the functionality that makes the related-object
+ # managers available as attributes on a model class, for fields that have
+ # a single "remote" value, on the class that defines the related field.
+ # In the example "choice.poll", the poll attribute is a
+ # ReverseSingleRelatedObjectDescriptor instance.
+ def __init__(self, field_with_rel):
+ self.field = field_with_rel
+
+ def __get__(self, instance, instance_type=None):
+ if instance is None:
+ return self
+
+ cache_name = self.field.get_cache_name()
+ try:
+ return getattr(instance, cache_name)
+ except AttributeError:
+ val = getattr(instance, self.field.attname)
+ if val is None:
+ # If NULL is an allowed value, return it.
+ if self.field.null:
+ return None
+ raise self.field.rel.to.DoesNotExist
+ other_field = self.field.rel.get_related_field()
+ if other_field.rel:
+ params = {'%s__pk' % self.field.rel.field_name: val}
+ else:
+ params = {'%s__exact' % self.field.rel.field_name: val}
+
+ # If the related manager indicates that it should be used for
+ # related fields, respect that.
+ rel_mgr = self.field.rel.to._default_manager
+ if getattr(rel_mgr, 'use_for_related_fields', False):
+ rel_obj = rel_mgr.get(**params)
+ else:
+ rel_obj = QuerySet(self.field.rel.to).get(**params)
+ setattr(instance, cache_name, rel_obj)
+ return rel_obj
+
+ def __set__(self, instance, value):
+ if instance is None:
+ raise AttributeError, "%s must be accessed via instance" % self._field.name
+
+ # 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 == 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))
+
+ # 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.field.get_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:
+ cache_name = '_%s_cache' % self.field.related.get_accessor_name()
+ try:
+ delattr(related, cache_name)
+ except AttributeError:
+ pass
+
+ # Set the value of the related field
+ try:
+ val = getattr(value, self.field.rel.get_related_field().attname)
+ except AttributeError:
+ val = None
+ setattr(instance, self.field.attname, val)
+
+ # Since we already know what the related object is, seed the related
+ # object cache now, too. This avoids another db hit if you get the
+ # object you just set.
+ setattr(instance, self.field.get_cache_name(), value)
+
+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.create_manager(instance,
+ self.related.model._default_manager.__class__)
+
+ def __set__(self, instance, value):
+ if instance is None:
+ raise AttributeError, "Manager must be accessed via instance"
+
+ 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)
+
+ def delete_manager(self, instance):
+ """
+ Returns a queryset based on the related model's base manager (rather
+ than the default manager, as returned by __get__). Used by
+ Model.delete().
+ """
+ return self.create_manager(instance,
+ self.related.model._base_manager.__class__)
+
+ def create_manager(self, instance, superclass):
+ """
+ Creates the managers used by other methods (__get__() and delete()).
+ """
+ rel_field = self.related.field
+ rel_model = self.related.model
+
+ class RelatedManager(superclass):
+ def get_query_set(self):
+ return superclass.get_query_set(self).filter(**(self.core_filters))
+
+ def add(self, *objs):
+ for obj in objs:
+ if not isinstance(obj, self.model):
+ raise TypeError, "'%s' instance expected" % self.model._meta.object_name
+ setattr(obj, rel_field.name, instance)
+ obj.save()
+ add.alters_data = True
+
+ def create(self, **kwargs):
+ kwargs.update({rel_field.name: instance})
+ return super(RelatedManager, self).create(**kwargs)
+ create.alters_data = True
+
+ def get_or_create(self, **kwargs):
+ # Update kwargs with the related object that this
+ # ForeignRelatedObjectsDescriptor knows about.
+ kwargs.update({rel_field.name: instance})
+ return super(RelatedManager, self).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):
+ val = getattr(instance, rel_field.rel.get_related_field().attname)
+ for obj in objs:
+ # Is obj actually part of this descriptor set?
+ if getattr(obj, rel_field.attname) == val:
+ setattr(obj, rel_field.name, None)
+ obj.save()
+ else:
+ raise rel_field.rel.to.DoesNotExist, "%r is not related to %r." % (obj, instance)
+ remove.alters_data = True
+
+ def clear(self):
+ for obj in self.all():
+ setattr(obj, rel_field.name, None)
+ obj.save()
+ clear.alters_data = True
+
+ manager = RelatedManager()
+ attname = rel_field.rel.get_related_field().name
+ manager.core_filters = {'%s__%s' % (rel_field.name, attname):
+ getattr(instance, attname)}
+ manager.model = self.related.model
+
+ return manager
+
+def create_many_related_manager(superclass, through=False):
+ """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, core_filters=None, instance=None, symmetrical=None,
+ join_table=None, source_col_name=None, target_col_name=None):
+ super(ManyRelatedManager, self).__init__()
+ self.core_filters = core_filters
+ self.model = model
+ self.symmetrical = symmetrical
+ self.instance = instance
+ self.join_table = join_table
+ self.source_col_name = source_col_name
+ self.target_col_name = target_col_name
+ self.through = through
+ self._pk_val = self.instance._get_pk_val()
+ if self._pk_val 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 get_query_set(self):
+ return superclass.get_query_set(self)._next_is_sticky().filter(**(self.core_filters))
+
+ # If the ManyToMany relation has an intermediary model,
+ # the add and remove methods do not exist.
+ if through is None:
+ def add(self, *objs):
+ self._add_items(self.source_col_name, self.target_col_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_col_name, self.source_col_name, *objs)
+ add.alters_data = True
+
+ def remove(self, *objs):
+ self._remove_items(self.source_col_name, self.target_col_name, *objs)
+
+ # If this is a symmetrical m2m relation to self, remove the mirror entry in the m2m table
+ if self.symmetrical:
+ self._remove_items(self.target_col_name, self.source_col_name, *objs)
+ remove.alters_data = True
+
+ def clear(self):
+ self._clear_items(self.source_col_name)
+
+ # If this is a symmetrical m2m relation to self, clear the mirror entry in the m2m table
+ if self.symmetrical:
+ self._clear_items(self.target_col_name)
+ 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 through is not None:
+ raise AttributeError, "Cannot use create() on a ManyToManyField which specifies an intermediary model. Use %s's Manager instead." % through
+ new_obj = super(ManyRelatedManager, self).create(**kwargs)
+ self.add(new_obj)
+ return new_obj
+ create.alters_data = True
+
+ def get_or_create(self, **kwargs):
+ obj, created = \
+ super(ManyRelatedManager, self).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_col_name, target_col_name, *objs):
+ # join_table: name of the m2m link table
+ # source_col_name: the PK colname in join_table for the source object
+ # target_col_name: the PK colname 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.
+ if objs:
+ from django.db.models.base import Model
+ # Check that all the objects are of the right type
+ new_ids = set()
+ for obj in objs:
+ if isinstance(obj, self.model):
+ new_ids.add(obj._get_pk_val())
+ elif isinstance(obj, Model):
+ raise TypeError, "'%s' instance expected" % self.model._meta.object_name
+ else:
+ new_ids.add(obj)
+ # Add the newly created or already existing objects to the join table.
+ # First find out which items are already added, to avoid adding them twice
+ cursor = connection.cursor()
+ cursor.execute("SELECT %s FROM %s WHERE %s = %%s AND %s IN (%s)" % \
+ (target_col_name, self.join_table, source_col_name,
+ target_col_name, ",".join(['%s'] * len(new_ids))),
+ [self._pk_val] + list(new_ids))
+ existing_ids = set([row[0] for row in cursor.fetchall()])
+
+ # Add the ones that aren't there already
+ for obj_id in (new_ids - existing_ids):
+ cursor.execute("INSERT INTO %s (%s, %s) VALUES (%%s, %%s)" % \
+ (self.join_table, source_col_name, target_col_name),
+ [self._pk_val, obj_id])
+ transaction.commit_unless_managed()
+
+ def _remove_items(self, source_col_name, target_col_name, *objs):
+ # source_col_name: the PK colname in join_table for the source object
+ # target_col_name: the PK colname in join_table for the target object
+ # *objs - objects to remove
+
+ # If there aren't any objects, there is nothing to do.
+ if objs:
+ # Check that all the objects are of the right type
+ old_ids = set()
+ for obj in objs:
+ if isinstance(obj, self.model):
+ old_ids.add(obj._get_pk_val())
+ else:
+ old_ids.add(obj)
+ # Remove the specified objects from the join table
+ cursor = connection.cursor()
+ cursor.execute("DELETE FROM %s WHERE %s = %%s AND %s IN (%s)" % \
+ (self.join_table, source_col_name,
+ target_col_name, ",".join(['%s'] * len(old_ids))),
+ [self._pk_val] + list(old_ids))
+ transaction.commit_unless_managed()
+
+ def _clear_items(self, source_col_name):
+ # source_col_name: the PK colname in join_table for the source object
+ cursor = connection.cursor()
+ cursor.execute("DELETE FROM %s WHERE %s = %%s" % \
+ (self.join_table, source_col_name),
+ [self._pk_val])
+ transaction.commit_unless_managed()
+
+ 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
+
+ def __get__(self, instance, instance_type=None):
+ if instance is None:
+ return self
+
+ # Dynamically create a class that subclasses the related
+ # model's default manager.
+ rel_model = self.related.model
+ superclass = rel_model._default_manager.__class__
+ RelatedManager = create_many_related_manager(superclass, self.related.field.rel.through)
+
+ qn = connection.ops.quote_name
+ manager = RelatedManager(
+ model=rel_model,
+ core_filters={'%s__pk' % self.related.field.name: instance._get_pk_val()},
+ instance=instance,
+ symmetrical=False,
+ join_table=qn(self.related.field.m2m_db_table()),
+ source_col_name=qn(self.related.field.m2m_reverse_name()),
+ target_col_name=qn(self.related.field.m2m_column_name())
+ )
+
+ return manager
+
+ def __set__(self, instance, value):
+ if instance is None:
+ raise AttributeError, "Manager must be accessed via instance"
+
+ through = getattr(self.related.field.rel, 'through', None)
+ if through is not None:
+ raise AttributeError, "Cannot set values on a ManyToManyField which specifies an intermediary model. Use %s's Manager instead." % through
+
+ 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
+
+ def __get__(self, instance, instance_type=None):
+ if instance is None:
+ return self
+
+ # Dynamically create a class that subclasses the related
+ # model's default manager.
+ rel_model=self.field.rel.to
+ superclass = rel_model._default_manager.__class__
+ RelatedManager = create_many_related_manager(superclass, self.field.rel.through)
+
+ qn = connection.ops.quote_name
+ manager = RelatedManager(
+ model=rel_model,
+ core_filters={'%s__pk' % self.field.related_query_name(): instance._get_pk_val()},
+ instance=instance,
+ symmetrical=(self.field.rel.symmetrical and isinstance(instance, rel_model)),
+ join_table=qn(self.field.m2m_db_table()),
+ source_col_name=qn(self.field.m2m_column_name()),
+ target_col_name=qn(self.field.m2m_reverse_name())
+ )
+
+ return manager
+
+ def __set__(self, instance, value):
+ if instance is None:
+ raise AttributeError, "Manager must be accessed via instance"
+
+ through = getattr(self.field.rel, 'through', None)
+ if through is not None:
+ raise AttributeError, "Cannot set values on a ManyToManyField which specifies an intermediary model. Use %s's Manager instead." % through
+
+ manager = self.__get__(instance)
+ manager.clear()
+ manager.add(*value)
+
+class ManyToOneRel(object):
+ def __init__(self, to, field_name, related_name=None,
+ limit_choices_to=None, lookup_overrides=None, parent_link=False):
+ try:
+ to._meta
+ except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
+ assert isinstance(to, basestring), "'to' must be either a model, a model name or the string %r" % RECURSIVE_RELATIONSHIP_CONSTANT
+ self.to, self.field_name = to, field_name
+ self.related_name = related_name
+ if limit_choices_to is None:
+ limit_choices_to = {}
+ self.limit_choices_to = limit_choices_to
+ self.lookup_overrides = lookup_overrides or {}
+ self.multiple = True
+ self.parent_link = parent_link
+
+ 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]
+
+class OneToOneRel(ManyToOneRel):
+ def __init__(self, to, field_name, related_name=None,
+ limit_choices_to=None, lookup_overrides=None, parent_link=False):
+ super(OneToOneRel, self).__init__(to, field_name,
+ related_name=related_name, limit_choices_to=limit_choices_to,
+ lookup_overrides=lookup_overrides, parent_link=parent_link)
+ self.multiple = False
+
+class ManyToManyRel(object):
+ def __init__(self, to, related_name=None, limit_choices_to=None,
+ symmetrical=True, through=None):
+ self.to = to
+ self.related_name = related_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
+
+ 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 ForeignKey(RelatedField, Field):
+ empty_strings_allowed = False
+ def __init__(self, to, to_field=None, rel_class=ManyToOneRel, **kwargs):
+ try:
+ to_name = to._meta.object_name.lower()
+ except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
+ assert isinstance(to, basestring), "%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:
+ assert not to._meta.abstract, "%s cannot define a relation with abstract class %s" % (self.__class__.__name__, to._meta.object_name)
+ to_field = to_field or to._meta.pk.name
+ kwargs['verbose_name'] = kwargs.get('verbose_name', None)
+
+ kwargs['rel'] = rel_class(to, to_field,
+ related_name=kwargs.pop('related_name', None),
+ limit_choices_to=kwargs.pop('limit_choices_to', None),
+ lookup_overrides=kwargs.pop('lookup_overrides', None),
+ parent_link=kwargs.pop('parent_link', False))
+ Field.__init__(self, **kwargs)
+
+ self.db_index = True
+
+ def get_attname(self):
+ return '%s_id' % self.name
+
+ def get_validator_unique_lookup_type(self):
+ return '%s__%s__exact' % (self.name, self.rel.get_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.rel.get_related_field().attname)
+ return field_default
+
+ def get_db_prep_save(self, value):
+ if value == '' or value == None:
+ return None
+ else:
+ return self.rel.get_related_field().get_db_prep_save(value)
+
+ 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_unicode(choice_list[1][0])
+ return Field.value_to_string(self, obj)
+
+ def contribute_to_class(self, cls, name):
+ super(ForeignKey, self).contribute_to_class(cls, name)
+ setattr(cls, self.name, ReverseSingleRelatedObjectDescriptor(self))
+ if isinstance(self.rel.to, basestring):
+ target = self.rel.to
+ else:
+ target = self.rel.to._meta.db_table
+ cls._meta.duplicate_targets[self.column] = (target, "o2m")
+
+ def contribute_to_related_class(self, cls, related):
+ setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related))
+
+ def formfield(self, **kwargs):
+ defaults = {
+ 'form_class': forms.ModelChoiceField,
+ 'queryset': self.rel.to._default_manager.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):
+ # 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.rel.get_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()
+ return rel_field.db_type()
+
+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.
+ """
+ def __init__(self, to, to_field=None, **kwargs):
+ kwargs['unique'] = True
+ super(OneToOneField, self).__init__(to, to_field, OneToOneRel, **kwargs)
+
+ def contribute_to_related_class(self, cls, related):
+ setattr(cls, related.get_accessor_name(),
+ SingleRelatedObjectDescriptor(related))
+
+ def formfield(self, **kwargs):
+ if self.rel.parent_link:
+ return None
+ return super(OneToOneField, self).formfield(**kwargs)
+
+class ManyToManyField(RelatedField, Field):
+ def __init__(self, to, **kwargs):
+ try:
+ assert not to._meta.abstract, "%s cannot define a relation with abstract class %s" % (self.__class__.__name__, to._meta.object_name)
+ except AttributeError: # to._meta doesn't exist, so it must be RECURSIVE_RELATIONSHIP_CONSTANT
+ assert isinstance(to, basestring), "%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)
+
+ kwargs['verbose_name'] = kwargs.get('verbose_name', None)
+ kwargs['rel'] = ManyToManyRel(to,
+ related_name=kwargs.pop('related_name', None),
+ limit_choices_to=kwargs.pop('limit_choices_to', None),
+ symmetrical=kwargs.pop('symmetrical', True),
+ through=kwargs.pop('through', None))
+
+ self.db_table = kwargs.pop('db_table', None)
+ if kwargs['rel'].through is not None:
+ self.creates_table = False
+ assert self.db_table is None, "Cannot specify a db_table if an intermediary model is used."
+ else:
+ self.creates_table = True
+
+ Field.__init__(self, **kwargs)
+
+ msg = ugettext_lazy('Hold down "Control", or "Command" on a Mac, to select more than one.')
+ self.help_text = string_concat(self.help_text, ' ', msg)
+
+ 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_model._meta.db_table
+ elif self.db_table:
+ return self.db_table
+ else:
+ return util.truncate_name('%s_%s' % (opts.db_table, self.name),
+ connection.ops.max_name_length())
+
+ def _get_m2m_column_name(self, related):
+ "Function that can be curried to provide the source column name for the m2m table"
+ try:
+ return self._m2m_column_name_cache
+ except:
+ if self.rel.through is not None:
+ for f in self.rel.through_model._meta.fields:
+ if hasattr(f,'rel') and f.rel and f.rel.to == related.model:
+ self._m2m_column_name_cache = f.column
+ break
+ # If this is an m2m relation to self, avoid the inevitable name clash
+ elif related.model == related.parent_model:
+ self._m2m_column_name_cache = 'from_' + related.model._meta.object_name.lower() + '_id'
+ else:
+ self._m2m_column_name_cache = related.model._meta.object_name.lower() + '_id'
+
+ # Return the newly cached value
+ return self._m2m_column_name_cache
+
+ def _get_m2m_reverse_name(self, related):
+ "Function that can be curried to provide the related column name for the m2m table"
+ try:
+ return self._m2m_reverse_name_cache
+ except:
+ if self.rel.through is not None:
+ found = False
+ for f in self.rel.through_model._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:
+ self._m2m_reverse_name_cache = f.column
+ break
+ else:
+ found = True
+ else:
+ self._m2m_reverse_name_cache = f.column
+ break
+ # If this is an m2m relation to self, avoid the inevitable name clash
+ elif related.model == related.parent_model:
+ self._m2m_reverse_name_cache = 'to_' + related.parent_model._meta.object_name.lower() + '_id'
+ else:
+ self._m2m_reverse_name_cache = related.parent_model._meta.object_name.lower() + '_id'
+
+ # Return the newly cached value
+ return self._m2m_reverse_name_cache
+
+ def isValidIDList(self, field_data, all_data):
+ "Validates that the value is a valid list of foreign keys"
+ mod = self.rel.to
+ try:
+ pks = map(int, field_data.split(','))
+ except ValueError:
+ # the CommaSeparatedIntegerField validator will catch this error
+ return
+ objects = mod._default_manager.in_bulk(pks)
+ if len(objects) != len(pks):
+ badkeys = [k for k in pks if k not in objects]
+ raise exceptions.ValidationError(
+ ungettext("Please enter valid %(self)s IDs. The value %(value)r is invalid.",
+ "Please enter valid %(self)s IDs. The values %(value)r are invalid.",
+ len(badkeys)) % {
+ 'self': self.verbose_name,
+ 'value': len(badkeys) == 1 and badkeys[0] or tuple(badkeys),
+ })
+
+ 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_unicode(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" and self.rel.related_name is None:
+ self.rel.related_name = "%s_rel_+" % name
+
+ super(ManyToManyField, self).contribute_to_class(cls, name)
+ # 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, basestring):
+ def resolve_through_model(field, model, cls):
+ field.rel.through_model = model
+ add_lazy_relation(cls, self, self.rel.through, resolve_through_model)
+ elif self.rel.through:
+ self.rel.through_model = self.rel.through
+ self.rel.through = self.rel.through._meta.object_name
+
+ if isinstance(self.rel.to, basestring):
+ target = self.rel.to
+ else:
+ target = self.rel.to._meta.db_table
+ cls._meta.duplicate_targets[self.column] = (target, "m2m")
+
+ def contribute_to_related_class(self, cls, related):
+ # m2m relations to self do not have a ManyRelatedObjectsDescriptor,
+ # as it would be redundant - unless the field is non-symmetrical.
+ if related.model != related.parent_model or not self.rel.symmetrical:
+ # Add the descriptor for the m2m relation
+ 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_column_name, related)
+ self.m2m_reverse_name = curry(self._get_m2m_reverse_name, related)
+
+ 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):
+ defaults = {'form_class': forms.ModelMultipleChoiceField, 'queryset': self.rel.to._default_manager.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):
+ # A ManyToManyField is not represented by a single column,
+ # so return None.
+ return None