MERGED MAGIC-REMOVAL BRANCH TO TRUNK. This change is highly backwards-incompatible. Please read http://code.djangoproject.com/wiki/RemovingTheMagic for upgrade instructions.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@2809 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 718 insertions, 0 deletions

diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
new file mode 100644
index 0000000000..908aa75207
--- /dev/null
+++ b/django/db/models/fields/related.py
@@ -0,0 +1,718 @@
+from django.db import backend, connection, transaction
+from django.db.models import signals
+from django.db.models.fields import AutoField, Field, IntegerField, get_ul_class
+from django.db.models.related import RelatedObject
+from django.utils.translation import gettext_lazy, string_concat
+from django.utils.functional import curry
+from django.core import validators
+from django import forms
+from django.dispatch import dispatcher
+
+# For Python 2.3
+if not hasattr(__builtins__, 'set'):
+    from sets import Set as set
+
+# Values for Relation.edit_inline.
+TABULAR, STACKED = 1, 2
+
+RECURSIVE_RELATIONSHIP_CONSTANT = 'self'
+
+pending_lookups = {}
+
+def add_lookup(rel_cls, field):
+    name = field.rel.to
+    module = rel_cls.__module__
+    key = (module, name)
+    pending_lookups.setdefault(key, []).append((rel_cls, field))
+
+def do_pending_lookups(sender):
+    other_cls = sender
+    key = (other_cls.__module__, other_cls.__name__)
+    for rel_cls, field in pending_lookups.setdefault(key, []):
+        field.rel.to = other_cls
+        field.do_related_class(other_cls, rel_cls)
+
+dispatcher.connect(do_pending_lookups, signal=signals.class_prepared)
+
+def manipulator_valid_rel_key(f, self, field_data, all_data):
+    "Validates that the value is a valid foreign key"
+    klass = f.rel.to
+    try:
+        klass._default_manager.get(pk=field_data)
+    except klass.DoesNotExist:
+        raise validators.ValidationError, _("Please enter a valid %s.") % f.verbose_name
+
+#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)
+        other = self.rel.to
+        if isinstance(other, basestring):
+            if other == RECURSIVE_RELATIONSHIP_CONSTANT:
+                self.rel.to = cls.__name__
+            add_lookup(cls, self)
+        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)
+        self.verbose_name = self.verbose_name or 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()
+        related = RelatedObject(other, cls, self)
+        self.contribute_to_related_class(other, related)
+
+    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
+
+    def __get__(self, instance, instance_type=None):
+        if instance is None:
+            raise AttributeError, "%s must be accessed via instance" % self.related.opts.object_name
+
+        params = {'%s__pk' % self.related.field.name: instance._get_pk_val()}
+        rel_obj = self.related.model._default_manager.get(**params)
+        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
+        # Set the value of the related field
+        setattr(value, self.related.field.rel.get_related_field().attname, instance)
+
+        # Clear the cache, if it exists
+        try:
+            delattr(value, self.related.field.get_cache_name())
+        except AttributeError:
+            pass
+
+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:
+            raise AttributeError, "%s must be accessed via instance" % self.field.name
+        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}
+            rel_obj = self.field.rel.to._default_manager.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
+        # 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)
+
+        # Clear the cache, if it exists
+        try:
+            delattr(instance, self.field.get_cache_name())
+        except AttributeError:
+            pass
+
+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:
+            raise AttributeError, "Manager must be accessed via instance"
+
+        rel_field = self.related.field
+        rel_model = self.related.model
+
+        # Dynamically create a class that subclasses the related
+        # model's default manager.
+        superclass = self.related.model._default_manager.__class__
+
+        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:
+                    setattr(obj, rel_field.name, instance)
+                    obj.save()
+            add.alters_data = True
+
+            def create(self, **kwargs):
+                new_obj = self.model(**kwargs)
+                self.add(new_obj)
+                return new_obj
+            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, "'%s' is not related to '%s'." % (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()
+        manager.core_filters = {'%s__pk' % rel_field.name: getattr(instance, rel_field.rel.get_related_field().attname)}
+        manager.model = self.related.model
+
+        return manager
+
+    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()
+        for obj in value:
+            manager.add(obj)
+
+def create_many_related_manager(superclass):
+    """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
+            if instance:
+                self._pk_val = self.instance._get_pk_val()
+
+        def get_query_set(self):
+            return superclass.get_query_set(self).filter(**(self.core_filters))
+
+        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):
+            new_obj = self.model(**kwargs)
+            new_obj.save()
+            self.add(new_obj)
+            return new_obj
+        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
+            from django.db import connection
+
+            # 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
+            new_ids = set([obj._get_pk_val() for obj in objs])
+            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))
+            if cursor.rowcount is not None and cursor.rowcount != 0:
+                existing_ids = set([row[0] for row in cursor.fetchmany(cursor.rowcount)])
+            else:
+                existing_ids = set()
+
+            # 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
+            from django.db import connection
+
+            for obj in objs:
+                if not isinstance(obj, self.model):
+                    raise ValueError, "objects to remove() must be %s instances" % self.model._meta.object_name
+            # Remove the specified objects from the join table
+            cursor = connection.cursor()
+            for obj in objs:
+                cursor.execute("DELETE FROM %s WHERE %s = %%s AND %s = %%s" % \
+                    (self.join_table, source_col_name, target_col_name),
+                    [self._pk_val, obj._get_pk_val()])
+            transaction.commit_unless_managed()
+
+        def _clear_items(self, source_col_name):
+            # source_col_name: the PK colname in join_table for the source object
+            from django.db import connection
+            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:
+            raise AttributeError, "Manager must be accessed via instance"
+
+        # 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)
+
+        qn = backend.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"
+
+        manager = self.__get__(instance)
+        manager.clear()
+        for obj in value:
+            manager.add(obj)
+
+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:
+            raise AttributeError, "Manager must be accessed via instance"
+
+        # 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)
+
+        qn = backend.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 instance.__class__ == 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"
+
+        manager = self.__get__(instance)
+        manager.clear()
+        for obj in value:
+            manager.add(obj)
+
+class ForeignKey(RelatedField, Field):
+    empty_strings_allowed = False
+    def __init__(self, to, to_field=None, **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), "ForeignKey(%r) is invalid. First parameter to ForeignKey must be either a model, a model name, or the string %r" % (to, RECURSIVE_RELATIONSHIP_CONSTANT)
+        else:
+            to_field = to_field or to._meta.pk.name
+        kwargs['verbose_name'] = kwargs.get('verbose_name', '')
+
+        if kwargs.has_key('edit_inline_type'):
+            import warnings
+            warnings.warn("edit_inline_type is deprecated. Use edit_inline instead.")
+            kwargs['edit_inline'] = kwargs.pop('edit_inline_type')
+
+        kwargs['rel'] = ManyToOneRel(to, to_field,
+            num_in_admin=kwargs.pop('num_in_admin', 3),
+            min_num_in_admin=kwargs.pop('min_num_in_admin', None),
+            max_num_in_admin=kwargs.pop('max_num_in_admin', None),
+            num_extra_on_change=kwargs.pop('num_extra_on_change', 1),
+            edit_inline=kwargs.pop('edit_inline', False),
+            related_name=kwargs.pop('related_name', None),
+            limit_choices_to=kwargs.pop('limit_choices_to', None),
+            lookup_overrides=kwargs.pop('lookup_overrides', None),
+            raw_id_admin=kwargs.pop('raw_id_admin', 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 prepare_field_objs_and_params(self, manipulator, name_prefix):
+        params = {'validator_list': self.validator_list[:], 'member_name': name_prefix + self.attname}
+        if self.rel.raw_id_admin:
+            field_objs = self.get_manipulator_field_objs()
+            params['validator_list'].append(curry(manipulator_valid_rel_key, self, manipulator))
+        else:
+            if self.radio_admin:
+                field_objs = [forms.RadioSelectField]
+                params['ul_class'] = get_ul_class(self.radio_admin)
+            else:
+                if self.null:
+                    field_objs = [forms.NullSelectField]
+                else:
+                    field_objs = [forms.SelectField]
+            params['choices'] = self.get_choices_default()
+        return field_objs, params
+
+    def get_manipulator_field_objs(self):
+        rel_field = self.rel.get_related_field()
+        if self.rel.raw_id_admin and not isinstance(rel_field, AutoField):
+            return rel_field.get_manipulator_field_objs()
+        else:
+            return [forms.IntegerField]
+
+    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 flatten_data(self, follow, obj=None):
+        if not obj:
+            # In required many-to-one fields with only one available choice,
+            # select that one available choice. Note: For SelectFields
+            # (radio_admin=False), we have to check that the length of choices
+            # is *2*, not 1, because SelectFields always have an initial
+            # "blank" value. Otherwise (radio_admin=True), we check that the
+            # length is 1.
+            if not self.blank and (not self.rel.raw_id_admin or self.choices):
+                choice_list = self.get_choices_default()
+                if self.radio_admin and len(choice_list) == 1:
+                    return {self.attname: choice_list[0][0]}
+                if not self.radio_admin and len(choice_list) == 2:
+                    return {self.attname: choice_list[1][0]}
+        return Field.flatten_data(self, follow, obj)
+
+    def contribute_to_class(self, cls, name):
+        super(ForeignKey, self).contribute_to_class(cls, name)
+        setattr(cls, self.name, ReverseSingleRelatedObjectDescriptor(self))
+
+    def contribute_to_related_class(self, cls, related):
+        setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related))
+
+class OneToOneField(RelatedField, IntegerField):
+    def __init__(self, to, to_field=None, **kwargs):
+        kwargs['verbose_name'] = kwargs.get('verbose_name', '')
+        to_field = to_field or to._meta.pk.name
+
+        if kwargs.has_key('edit_inline_type'):
+            import warnings
+            warnings.warn("edit_inline_type is deprecated. Use edit_inline instead.")
+            kwargs['edit_inline'] = kwargs.pop('edit_inline_type')
+
+        kwargs['rel'] = OneToOneRel(to, to_field,
+            num_in_admin=kwargs.pop('num_in_admin', 0),
+            edit_inline=kwargs.pop('edit_inline', False),
+            related_name=kwargs.pop('related_name', None),
+            limit_choices_to=kwargs.pop('limit_choices_to', None),
+            lookup_overrides=kwargs.pop('lookup_overrides', None),
+            raw_id_admin=kwargs.pop('raw_id_admin', False))
+        kwargs['primary_key'] = True
+        IntegerField.__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)
+
+    # TODO: Copied from ForeignKey... putting this in RelatedField adversely affects
+    # ManyToManyField. This works for now.
+    def prepare_field_objs_and_params(self, manipulator, name_prefix):
+        params = {'validator_list': self.validator_list[:], 'member_name': name_prefix + self.attname}
+        if self.rel.raw_id_admin:
+            field_objs = self.get_manipulator_field_objs()
+            params['validator_list'].append(curry(manipulator_valid_rel_key, self, manipulator))
+        else:
+            if self.radio_admin:
+                field_objs = [forms.RadioSelectField]
+                params['ul_class'] = get_ul_class(self.radio_admin)
+            else:
+                if self.null:
+                    field_objs = [forms.NullSelectField]
+                else:
+                    field_objs = [forms.SelectField]
+            params['choices'] = self.get_choices_default()
+        return field_objs, params
+
+    def contribute_to_class(self, cls, name):
+        super(OneToOneField, self).contribute_to_class(cls, name)
+        setattr(cls, self.name, ReverseSingleRelatedObjectDescriptor(self))
+
+    def contribute_to_related_class(self, cls, related):
+        setattr(cls, related.get_accessor_name(), SingleRelatedObjectDescriptor(related))
+        if not cls._meta.one_to_one_field:
+            cls._meta.one_to_one_field = self
+
+class ManyToManyField(RelatedField, Field):
+    def __init__(self, to, **kwargs):
+        kwargs['verbose_name'] = kwargs.get('verbose_name', None)
+        kwargs['rel'] = ManyToManyRel(to, kwargs.pop('singular', None),
+            num_in_admin=kwargs.pop('num_in_admin', 0),
+            related_name=kwargs.pop('related_name', None),
+            filter_interface=kwargs.pop('filter_interface', None),
+            limit_choices_to=kwargs.pop('limit_choices_to', None),
+            raw_id_admin=kwargs.pop('raw_id_admin', False),
+            symmetrical=kwargs.pop('symmetrical', True))
+        if kwargs["rel"].raw_id_admin:
+            kwargs.setdefault("validator_list", []).append(self.isValidIDList)
+        Field.__init__(self, **kwargs)
+
+        if self.rel.raw_id_admin:
+            msg = gettext_lazy('Separate multiple IDs with commas.')
+        else:
+            msg = gettext_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_manipulator_field_objs(self):
+        if self.rel.raw_id_admin:
+            return [forms.RawIdAdminField]
+        else:
+            choices = self.get_choices_default()
+            return [curry(forms.SelectMultipleField, size=min(max(len(choices), 5), 15), choices=choices)]
+
+    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"
+        return '%s_%s' % (opts.db_table, self.name)
+
+    def _get_m2m_column_name(self, related):
+        "Function that can be curried to provide the source column name for the m2m table"
+        # If this is an m2m relation to self, avoid the inevitable name clash
+        if related.model == related.parent_model:
+            return 'from_' + related.model._meta.object_name.lower() + '_id'
+        else:
+            return related.model._meta.object_name.lower() + '_id'
+
+    def _get_m2m_reverse_name(self, related):
+        "Function that can be curried to provide the related column name for the m2m table"
+        # If this is an m2m relation to self, avoid the inevitable name clash
+        if related.model == related.parent_model:
+            return 'to_' + related.parent_model._meta.object_name.lower() + '_id'
+        else:
+            return related.parent_model._meta.object_name.lower() + '_id'
+
+    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 validators.ValidationError, ngettext("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 flatten_data(self, follow, obj = None):
+        new_data = {}
+        if obj:
+            instance_ids = [instance._get_pk_val() for instance in getattr(obj, self.name).all()]
+            if self.rel.raw_id_admin:
+                new_data[self.name] = ",".join([str(id) for id in instance_ids])
+            else:
+                new_data[self.name] = instance_ids
+        else:
+            # In required many-to-many fields with only one available choice,
+            # select that one available choice.
+            if not self.blank and not self.rel.edit_inline and not self.rel.raw_id_admin:
+                choices_list = self.get_choices_default()
+                if len(choices_list) == 1:
+                    new_data[self.name] = [choices_list[0][0]]
+        return new_data
+
+    def contribute_to_class(self, cls, 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)
+
+    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))
+
+        self.rel.singular = self.rel.singular or self.rel.to._meta.object_name.lower()
+
+        # 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
+
+class ManyToOneRel:
+    def __init__(self, to, field_name, num_in_admin=3, min_num_in_admin=None,
+        max_num_in_admin=None, num_extra_on_change=1, edit_inline=False,
+        related_name=None, limit_choices_to=None, lookup_overrides=None, raw_id_admin=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.num_in_admin, self.edit_inline = num_in_admin, edit_inline
+        self.min_num_in_admin, self.max_num_in_admin = min_num_in_admin, max_num_in_admin
+        self.num_extra_on_change, self.related_name = num_extra_on_change, related_name
+        self.limit_choices_to = limit_choices_to or {}
+        self.lookup_overrides = lookup_overrides or {}
+        self.raw_id_admin = raw_id_admin
+        self.multiple = True
+
+    def get_related_field(self):
+        "Returns the Field in the 'to' object to which this relationship is tied."
+        return self.to._meta.get_field(self.field_name)
+
+class OneToOneRel(ManyToOneRel):
+    def __init__(self, to, field_name, num_in_admin=0, edit_inline=False,
+        related_name=None, limit_choices_to=None, lookup_overrides=None,
+        raw_id_admin=False):
+        self.to, self.field_name = to, field_name
+        self.num_in_admin, self.edit_inline = num_in_admin, edit_inline
+        self.related_name = related_name
+        self.limit_choices_to = limit_choices_to or {}
+        self.lookup_overrides = lookup_overrides or {}
+        self.raw_id_admin = raw_id_admin
+        self.multiple = False
+
+class ManyToManyRel:
+    def __init__(self, to, singular=None, num_in_admin=0, related_name=None,
+        filter_interface=None, limit_choices_to=None, raw_id_admin=False, symmetrical=True):
+        self.to = to
+        self.singular = singular or None
+        self.num_in_admin = num_in_admin
+        self.related_name = related_name
+        self.filter_interface = filter_interface
+        self.limit_choices_to = limit_choices_to or {}
+        self.edit_inline = False
+        self.raw_id_admin = raw_id_admin
+        self.symmetrical = symmetrical
+        self.multiple = True
+
+        assert not (self.raw_id_admin and self.filter_interface), "ManyToManyRels may not use both raw_id_admin and filter_interface"