Python django.db.models.fields.AutoField() Examples

def get_django_field_map(self):
        from django.db.models import fields as djf
        return [
            (djf.AutoField, PrimaryKeyField),
            (djf.BigIntegerField, BigIntegerField),
            # (djf.BinaryField, BlobField),
            (djf.BooleanField, BooleanField),
            (djf.CharField, CharField),
            (djf.DateTimeField, DateTimeField),  # Extends DateField.
            (djf.DateField, DateField),
            (djf.DecimalField, DecimalField),
            (djf.FilePathField, CharField),
            (djf.FloatField, FloatField),
            (djf.IntegerField, IntegerField),
            (djf.NullBooleanField, partial(BooleanField, null=True)),
            (djf.TextField, TextField),
            (djf.TimeField, TimeField),
            (djf.related.ForeignKey, ForeignKeyField),
        ] 

def __init__(self, field, request, params, model, model_admin, field_path):
        super().__init__(field, request, params, model, model_admin, field_path)

        if not isinstance(field, (DecimalField, IntegerField, FloatField, AutoField)):
            raise TypeError('Class {} is not supported for {}.'.format(type(self.field), self.__class__.__name__))

        self.request = request

        if self.parameter_name is None:
            self.parameter_name = self.field.name

        if self.parameter_name + '_from' in params:
            value = params.pop(self.parameter_name + '_from')
            self.used_parameters[self.parameter_name + '_from'] = value

        if self.parameter_name + '_to' in params:
            value = params.pop(self.parameter_name + '_to')
            self.used_parameters[self.parameter_name + '_to'] = value 

def _prepare(self, model):
        if self.order_with_respect_to:
            # The app registry will not be ready at this point, so we cannot
            # use get_field().
            query = self.order_with_respect_to
            try:
                self.order_with_respect_to = next(
                    f for f in self._get_fields(reverse=False)
                    if f.name == query or f.attname == query
                )
            except StopIteration:
                raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, query))

            self.ordering = ('_order',)
            if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
                model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(six.itervalues(self.parents))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
                if not field.remote_field.parent_link:
                    warnings.warn(
                        'Add parent_link=True to %s as an implicit link is '
                        'deprecated.' % field, RemovedInDjango20Warning
                    )
            else:
                auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True)
                model.add_to_class('id', auto) 

def get_field_nullability(self, field: Union[Field, ForeignObjectRel], method: Optional[str]) -> bool:
        nullable = field.null
        if not nullable and isinstance(field, CharField) and field.blank:
            return True
        if method == '__init__':
            if ((isinstance(field, Field) and field.primary_key)
                    or isinstance(field, ForeignKey)):
                return True
        if method == 'create':
            if isinstance(field, AutoField):
                return True
        if isinstance(field, Field) and field.has_default():
            return True
        return nullable 

def _prepare(self, model):
        if self.order_with_respect_to:
            # The app registry will not be ready at this point, so we cannot
            # use get_field().
            query = self.order_with_respect_to
            try:
                self.order_with_respect_to = next(
                    f for f in self._get_fields(reverse=False)
                    if f.name == query or f.attname == query
                )
            except StopIteration:
                raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, query))

            self.ordering = ('_order',)
            if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
                model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(six.itervalues(self.parents))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
                if not field.remote_field.parent_link:
                    warnings.warn(
                        'Add parent_link=True to %s as an implicit link is '
                        'deprecated.' % field, RemovedInDjango20Warning
                    )
            else:
                auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True)
                model.add_to_class('id', auto) 

def _prepare(self, model):
        if self.order_with_respect_to:
            # The app registry will not be ready at this point, so we cannot
            # use get_field().
            query = self.order_with_respect_to
            try:
                self.order_with_respect_to = next(
                    f for f in self._get_fields(reverse=False)
                    if f.name == query or f.attname == query
                )
            except StopIteration:
                raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, query))

            self.ordering = ('_order',)
            if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
                model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(six.itervalues(self.parents))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
            else:
                auto = AutoField(verbose_name='ID', primary_key=True,
                        auto_created=True)
                model.add_to_class('id', auto) 

def _prepare(self, model):
        if self.order_with_respect_to:
            # The app registry will not be ready at this point, so we cannot
            # use get_field().
            query = self.order_with_respect_to
            try:
                self.order_with_respect_to = next(
                    f for f in self._get_fields(reverse=False)
                    if f.name == query or f.attname == query
                )
            except StopIteration:
                raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, query))

            self.ordering = ('_order',)
            if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
                model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(iter(self.parents.values()))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
                if not field.remote_field.parent_link:
                    raise ImproperlyConfigured(
                        'Add parent_link=True to %s.' % field,
                    )
            else:
                auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True)
                model.add_to_class('id', auto) 

def _prepare(self, model):
        if self.order_with_respect_to:
            # The app registry will not be ready at this point, so we cannot
            # use get_field().
            query = self.order_with_respect_to
            try:
                self.order_with_respect_to = next(
                    f for f in self._get_fields(reverse=False)
                    if f.name == query or f.attname == query
                )
            except StopIteration:
                raise FieldDoesNotExist("%s has no field named '%s'" % (self.object_name, query))

            self.ordering = ('_order',)
            if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
                model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(iter(self.parents.values()))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
                if not field.remote_field.parent_link:
                    raise ImproperlyConfigured(
                        'Add parent_link=True to %s.' % field,
                    )
            else:
                auto = AutoField(verbose_name='ID', primary_key=True, auto_created=True)
                model.add_to_class('id', auto) 

def __init__(self, field, request, params, model, model_admin, field_path):
        super().__init__(field, request, params, model, model_admin, field_path)

        if not isinstance(field, (DecimalField, IntegerField, FloatField, AutoField)):
            raise TypeError('Class {} is not supported for {}.'.format(type(self.field), self.__class__.__name__))

        self.request = request

        if self.parameter_name is None:
            self.parameter_name = self.field.name

        if self.parameter_name in params:
            value = params.pop(self.parameter_name)
            self.used_parameters[self.parameter_name] = value 

def bulk_create(self, objs, batch_size=None):
        """
        Inserts each of the instances into the database. This does *not* call
        save() on each of the instances, does not send any pre/post save
        signals, and does not set the primary key attribute if it is an
        autoincrement field.
        """
        # So this case is fun. When you bulk insert you don't get the primary
        # keys back (if it's an autoincrement), so you can't insert into the
        # child tables which references this. There are two workarounds, 1)
        # this could be implemented if you didn't have an autoincrement pk,
        # and 2) you could do it by doing O(n) normal inserts into the parent
        # tables to get the primary keys back, and then doing a single bulk
        # insert into the childmost table. Some databases might allow doing
        # this by using RETURNING clause for the insert query. We're punting
        # on these for now because they are relatively rare cases.
        assert batch_size is None or batch_size > 0
        if self.model._meta.parents:
            raise ValueError("Can't bulk create an inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.local_concrete_fields
        objs = list(objs)
        self._populate_pk_values(objs)
        with transaction.atomic(using=self.db, savepoint=False):
            if (connection.features.can_combine_inserts_with_and_without_auto_increment_pk
                    and self.model._meta.has_auto_field):
                self._batched_insert(objs, fields, batch_size)
            else:
                objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
                if objs_with_pk:
                    self._batched_insert(objs_with_pk, fields, batch_size)
                if objs_without_pk:
                    fields = [f for f in fields if not isinstance(f, AutoField)]
                    self._batched_insert(objs_without_pk, fields, batch_size)

        return objs 

def _prepare(self, model):
        if self.order_with_respect_to:
            # The app registry will not be ready at this point, so we cannot
            # use get_field().
            query = self.order_with_respect_to
            try:
                self.order_with_respect_to = next(
                    f for f in self._get_fields(reverse=False)
                    if f.name == query or f.attname == query
                )
            except StopIteration:
                raise FieldDoesNotExist('%s has no field named %r' % (self.object_name, query))

            self.ordering = ('_order',)
            if not any(isinstance(field, OrderWrt) for field in model._meta.local_fields):
                model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(six.itervalues(self.parents))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
            else:
                auto = AutoField(verbose_name='ID', primary_key=True,
                        auto_created=True)
                model.add_to_class('id', auto) 

def bulk_create(self, objs, batch_size=None):
        """
        Insert each of the instances into the database. Do *not* call
        save() on each of the instances, do not send any pre/post_save
        signals, and do not set the primary key attribute if it is an
        autoincrement field (except if features.can_return_ids_from_bulk_insert=True).
        Multi-table models are not supported.
        """
        # When you bulk insert you don't get the primary keys back (if it's an
        # autoincrement, except if can_return_ids_from_bulk_insert=True), so
        # you can't insert into the child tables which references this. There
        # are two workarounds:
        # 1) This could be implemented if you didn't have an autoincrement pk
        # 2) You could do it by doing O(n) normal inserts into the parent
        #    tables to get the primary keys back and then doing a single bulk
        #    insert into the childmost table.
        # We currently set the primary keys on the objects when using
        # PostgreSQL via the RETURNING ID clause. It should be possible for
        # Oracle as well, but the semantics for  extracting the primary keys is
        # trickier so it's not done yet.
        assert batch_size is None or batch_size > 0
        # Check that the parents share the same concrete model with the our
        # model to detect the inheritance pattern ConcreteGrandParent ->
        # MultiTableParent -> ProxyChild. Simply checking self.model._meta.proxy
        # would not identify that case as involving multiple tables.
        for parent in self.model._meta.get_parent_list():
            if parent._meta.concrete_model is not self.model._meta.concrete_model:
                raise ValueError("Can't bulk create a multi-table inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.concrete_fields
        objs = list(objs)
        self._populate_pk_values(objs)
        with transaction.atomic(using=self.db, savepoint=False):
            objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
            if objs_with_pk:
                self._batched_insert(objs_with_pk, fields, batch_size)
            if objs_without_pk:
                fields = [f for f in fields if not isinstance(f, AutoField)]
                ids = self._batched_insert(objs_without_pk, fields, batch_size)
                if connection.features.can_return_ids_from_bulk_insert:
                    assert len(ids) == len(objs_without_pk)
                for obj_without_pk, pk in zip(objs_without_pk, ids):
                    obj_without_pk.pk = pk
                    obj_without_pk._state.adding = False
                    obj_without_pk._state.db = self.db

        return objs 

def bulk_create(self, objs, batch_size=None):
        """
        Insert each of the instances into the database. Do *not* call
        save() on each of the instances, do not send any pre/post_save
        signals, and do not set the primary key attribute if it is an
        autoincrement field (except if features.can_return_ids_from_bulk_insert=True).
        Multi-table models are not supported.
        """
        # When you bulk insert you don't get the primary keys back (if it's an
        # autoincrement, except if can_return_ids_from_bulk_insert=True), so
        # you can't insert into the child tables which references this. There
        # are two workarounds:
        # 1) This could be implemented if you didn't have an autoincrement pk
        # 2) You could do it by doing O(n) normal inserts into the parent
        #    tables to get the primary keys back and then doing a single bulk
        #    insert into the childmost table.
        # We currently set the primary keys on the objects when using
        # PostgreSQL via the RETURNING ID clause. It should be possible for
        # Oracle as well, but the semantics for extracting the primary keys is
        # trickier so it's not done yet.
        assert batch_size is None or batch_size > 0
        # Check that the parents share the same concrete model with the our
        # model to detect the inheritance pattern ConcreteGrandParent ->
        # MultiTableParent -> ProxyChild. Simply checking self.model._meta.proxy
        # would not identify that case as involving multiple tables.
        for parent in self.model._meta.get_parent_list():
            if parent._meta.concrete_model is not self.model._meta.concrete_model:
                raise ValueError("Can't bulk create a multi-table inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.concrete_fields
        objs = list(objs)
        self._populate_pk_values(objs)
        with transaction.atomic(using=self.db, savepoint=False):
            objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
            if objs_with_pk:
                self._batched_insert(objs_with_pk, fields, batch_size)
                for obj_with_pk in objs_with_pk:
                    obj_with_pk._state.adding = False
                    obj_with_pk._state.db = self.db
            if objs_without_pk:
                fields = [f for f in fields if not isinstance(f, AutoField)]
                ids = self._batched_insert(objs_without_pk, fields, batch_size)
                if connection.features.can_return_ids_from_bulk_insert:
                    assert len(ids) == len(objs_without_pk)
                for obj_without_pk, pk in zip(objs_without_pk, ids):
                    obj_without_pk.pk = pk
                    obj_without_pk._state.adding = False
                    obj_without_pk._state.db = self.db

        return objs 

def bulk_create(self, objs, batch_size=None):
        """
        Inserts each of the instances into the database. This does *not* call
        save() on each of the instances, does not send any pre/post save
        signals, and does not set the primary key attribute if it is an
        autoincrement field (except if features.can_return_ids_from_bulk_insert=True).
        Multi-table models are not supported.
        """
        # When you bulk insert you don't get the primary keys back (if it's an
        # autoincrement, except if can_return_ids_from_bulk_insert=True), so
        # you can't insert into the child tables which references this. There
        # are two workarounds:
        # 1) This could be implemented if you didn't have an autoincrement pk
        # 2) You could do it by doing O(n) normal inserts into the parent
        #    tables to get the primary keys back and then doing a single bulk
        #    insert into the childmost table.
        # We currently set the primary keys on the objects when using
        # PostgreSQL via the RETURNING ID clause. It should be possible for
        # Oracle as well, but the semantics for  extracting the primary keys is
        # trickier so it's not done yet.
        assert batch_size is None or batch_size > 0
        # Check that the parents share the same concrete model with the our
        # model to detect the inheritance pattern ConcreteGrandParent ->
        # MultiTableParent -> ProxyChild. Simply checking self.model._meta.proxy
        # would not identify that case as involving multiple tables.
        for parent in self.model._meta.get_parent_list():
            if parent._meta.concrete_model is not self.model._meta.concrete_model:
                raise ValueError("Can't bulk create a multi-table inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.concrete_fields
        objs = list(objs)
        self._populate_pk_values(objs)
        with transaction.atomic(using=self.db, savepoint=False):
            objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
            if objs_with_pk:
                self._batched_insert(objs_with_pk, fields, batch_size)
            if objs_without_pk:
                fields = [f for f in fields if not isinstance(f, AutoField)]
                ids = self._batched_insert(objs_without_pk, fields, batch_size)
                if connection.features.can_return_ids_from_bulk_insert:
                    assert len(ids) == len(objs_without_pk)
                for obj_without_pk, pk in zip(objs_without_pk, ids):
                    obj_without_pk.pk = pk
                    obj_without_pk._state.adding = False
                    obj_without_pk._state.db = self.db

        return objs 

def _prepare(self, model):
        if self.order_with_respect_to:
            self.order_with_respect_to = self.get_field(self.order_with_respect_to)
            self.ordering = ('_order',)
            model.add_to_class('_order', OrderWrt())
        else:
            self.order_with_respect_to = None

        if self.pk is None:
            if self.parents:
                # Promote the first parent link in lieu of adding yet another
                # field.
                field = next(six.itervalues(self.parents))
                # Look for a local field with the same name as the
                # first parent link. If a local field has already been
                # created, use it instead of promoting the parent
                already_created = [fld for fld in self.local_fields if fld.name == field.name]
                if already_created:
                    field = already_created[0]
                field.primary_key = True
                self.setup_pk(field)
            else:
                auto = AutoField(verbose_name='ID', primary_key=True,
                        auto_created=True)
                model.add_to_class('id', auto)

        # Determine any sets of fields that are pointing to the same targets
        # (e.g. two ForeignKeys to the same remote model). The query
        # construction code needs to know this. At the end of this,
        # self.duplicate_targets will map each duplicate field column to the
        # columns it duplicates.
        collections = {}
        for column, target in six.iteritems(self.duplicate_targets):
            try:
                collections[target].add(column)
            except KeyError:
                collections[target] = set([column])
        self.duplicate_targets = {}
        for elt in six.itervalues(collections):
            if len(elt) == 1:
                continue
            for column in elt:
                self.duplicate_targets[column] = elt.difference(set([column])) 

def bulk_create(self, objs, batch_size=None):
        """
        Inserts each of the instances into the database. This does *not* call
        save() on each of the instances, does not send any pre/post save
        signals, and does not set the primary key attribute if it is an
        autoincrement field.
        """
        # So this case is fun. When you bulk insert you don't get the primary
        # keys back (if it's an autoincrement), so you can't insert into the
        # child tables which references this. There are two workarounds, 1)
        # this could be implemented if you didn't have an autoincrement pk,
        # and 2) you could do it by doing O(n) normal inserts into the parent
        # tables to get the primary keys back, and then doing a single bulk
        # insert into the childmost table. Some databases might allow doing
        # this by using RETURNING clause for the insert query. We're punting
        # on these for now because they are relatively rare cases.
        assert batch_size is None or batch_size > 0
        if self.model._meta.parents:
            raise ValueError("Can't bulk create an inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.local_fields
        if not transaction.is_managed(using=self.db):
            transaction.enter_transaction_management(using=self.db)
            forced_managed = True
        else:
            forced_managed = False
        try:
            if (connection.features.can_combine_inserts_with_and_without_auto_increment_pk
                and self.model._meta.has_auto_field):
                self._batched_insert(objs, fields, batch_size)
            else:
                objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
                if objs_with_pk:
                    self._batched_insert(objs_with_pk, fields, batch_size)
                if objs_without_pk:
                    fields= [f for f in fields if not isinstance(f, AutoField)]
                    self._batched_insert(objs_without_pk, fields, batch_size)
            if forced_managed:
                transaction.commit(using=self.db)
            else:
                transaction.commit_unless_managed(using=self.db)
        finally:
            if forced_managed:
                transaction.leave_transaction_management(using=self.db)

        return objs 

def _save_table(self, raw=False, cls=None, force_insert=False,
                    force_update=False, using=None, update_fields=None):
        """
        Does the heavy-lifting involved in saving. Updates or inserts the data
        for a single table.
        """
        meta = cls._meta
        non_pks = [f for f in meta.local_concrete_fields if not f.primary_key]

        if update_fields:
            non_pks = [f for f in non_pks
                       if f.name in update_fields or f.attname in update_fields]

        pk_val = self._get_pk_val(meta)
        if pk_val is None:
            pk_val = meta.pk.get_pk_value_on_save(self)
            setattr(self, meta.pk.attname, pk_val)
        pk_set = pk_val is not None
        if not pk_set and (force_update or update_fields):
            raise ValueError("Cannot force an update in save() with no primary key.")
        updated = False
        # If possible, try an UPDATE. If that doesn't update anything, do an INSERT.
        if pk_set and not force_insert:
            base_qs = cls._base_manager.using(using)
            values = [(f, None, (getattr(self, f.attname) if raw else f.pre_save(self, False)))
                      for f in non_pks]
            forced_update = update_fields or force_update
            updated = self._do_update(base_qs, using, pk_val, values, update_fields,
                                      forced_update)
            if force_update and not updated:
                raise DatabaseError("Forced update did not affect any rows.")
            if update_fields and not updated:
                raise DatabaseError("Save with update_fields did not affect any rows.")
        if not updated:
            if meta.order_with_respect_to:
                # If this is a model with an order_with_respect_to
                # autopopulate the _order field
                field = meta.order_with_respect_to
                filter_args = field.get_filter_kwargs_for_object(self)
                order_value = cls._base_manager.using(using).filter(**filter_args).count()
                self._order = order_value

            fields = meta.local_concrete_fields
            if not pk_set:
                fields = [f for f in fields if not isinstance(f, AutoField)]

            update_pk = bool(meta.has_auto_field and not pk_set)
            result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
            if update_pk:
                setattr(self, meta.pk.attname, result)
        return updated 

def bulk_create(self, objs, batch_size=None):
        """
        Inserts each of the instances into the database. This does *not* call
        save() on each of the instances, does not send any pre/post save
        signals, and does not set the primary key attribute if it is an
        autoincrement field. Multi-table models are not supported.
        """
        # So this case is fun. When you bulk insert you don't get the primary
        # keys back (if it's an autoincrement), so you can't insert into the
        # child tables which references this. There are two workarounds, 1)
        # this could be implemented if you didn't have an autoincrement pk,
        # and 2) you could do it by doing O(n) normal inserts into the parent
        # tables to get the primary keys back, and then doing a single bulk
        # insert into the childmost table. Some databases might allow doing
        # this by using RETURNING clause for the insert query. We're punting
        # on these for now because they are relatively rare cases.
        assert batch_size is None or batch_size > 0
        # Check that the parents share the same concrete model with the our
        # model to detect the inheritance pattern ConcreteGrandParent ->
        # MultiTableParent -> ProxyChild. Simply checking self.model._meta.proxy
        # would not identify that case as involving multiple tables.
        for parent in self.model._meta.get_parent_list():
            if parent._meta.concrete_model is not self.model._meta.concrete_model:
                raise ValueError("Can't bulk create a multi-table inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.concrete_fields
        objs = list(objs)
        self._populate_pk_values(objs)
        with transaction.atomic(using=self.db, savepoint=False):
            if (connection.features.can_combine_inserts_with_and_without_auto_increment_pk
                    and self.model._meta.has_auto_field):
                self._batched_insert(objs, fields, batch_size)
            else:
                objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
                if objs_with_pk:
                    self._batched_insert(objs_with_pk, fields, batch_size)
                if objs_without_pk:
                    fields = [f for f in fields if not isinstance(f, AutoField)]
                    self._batched_insert(objs_without_pk, fields, batch_size)

        return objs 

def bulk_create(self, objs, batch_size=None):
        """
        Inserts each of the instances into the database. This does *not* call
        save() on each of the instances, does not send any pre/post save
        signals, and does not set the primary key attribute if it is an
        autoincrement field (except if features.can_return_ids_from_bulk_insert=True).
        Multi-table models are not supported.
        """
        # When you bulk insert you don't get the primary keys back (if it's an
        # autoincrement, except if can_return_ids_from_bulk_insert=True), so
        # you can't insert into the child tables which references this. There
        # are two workarounds:
        # 1) This could be implemented if you didn't have an autoincrement pk
        # 2) You could do it by doing O(n) normal inserts into the parent
        #    tables to get the primary keys back and then doing a single bulk
        #    insert into the childmost table.
        # We currently set the primary keys on the objects when using
        # PostgreSQL via the RETURNING ID clause. It should be possible for
        # Oracle as well, but the semantics for  extracting the primary keys is
        # trickier so it's not done yet.
        assert batch_size is None or batch_size > 0
        # Check that the parents share the same concrete model with the our
        # model to detect the inheritance pattern ConcreteGrandParent ->
        # MultiTableParent -> ProxyChild. Simply checking self.model._meta.proxy
        # would not identify that case as involving multiple tables.
        for parent in self.model._meta.get_parent_list():
            if parent._meta.concrete_model is not self.model._meta.concrete_model:
                raise ValueError("Can't bulk create a multi-table inherited model")
        if not objs:
            return objs
        self._for_write = True
        connection = connections[self.db]
        fields = self.model._meta.concrete_fields
        objs = list(objs)
        self._populate_pk_values(objs)
        with transaction.atomic(using=self.db, savepoint=False):
            objs_with_pk, objs_without_pk = partition(lambda o: o.pk is None, objs)
            if objs_with_pk:
                self._batched_insert(objs_with_pk, fields, batch_size)
            if objs_without_pk:
                fields = [f for f in fields if not isinstance(f, AutoField)]
                ids = self._batched_insert(objs_without_pk, fields, batch_size)
                if connection.features.can_return_ids_from_bulk_insert:
                    assert len(ids) == len(objs_without_pk)
                for obj_without_pk, pk in zip(objs_without_pk, ids):
                    obj_without_pk.pk = pk
                    obj_without_pk._state.adding = False
                    obj_without_pk._state.db = self.db

        return objs 

def import_model(self, model, elements):
        """Import model instances from list of XML elements."""

        model.objects.all().delete()

        boolean_field_names = [
            f.name
            for f in model._meta.fields
            if isinstance(f, django_fields.BooleanField)
        ]

        table_name = model._meta.db_table
        column_names = [
            f.db_column or f.name
            for f in model._meta.fields
            if not isinstance(f, django_fields.AutoField)
        ]
        sql = "INSERT INTO {} ({}) VALUES ({})".format(
            table_name, ", ".join(column_names), ", ".join(["%s"] * len(column_names))
        )

        values = []

        for element in elements:
            row = {}

            for field_element in element:
                name = field_element.tag.lower()
                if name == "desc":
                    # "desc" is a really unhelpful field name if you're writing
                    # SQL!
                    name = "descr"
                elif name == "dnd":
                    # For consistency with the rest of the data, we rename
                    # "dnd" to "dndcd", as it is a foreign key field.
                    name = "dndcd"

                value = field_element.text
                row[name] = value

            for name in boolean_field_names:
                row[name] = name in row

            values.append([row.get(name) for name in column_names])

        with connection.cursor() as cursor:
            cursor.executemany(sql, values) 

def _save_table(self, raw=False, cls=None, force_insert=False,
                    force_update=False, using=None, update_fields=None):
        """
        Does the heavy-lifting involved in saving. Updates or inserts the data
        for a single table.
        """
        meta = cls._meta
        non_pks = [f for f in meta.local_concrete_fields if not f.primary_key]

        if update_fields:
            non_pks = [f for f in non_pks
                       if f.name in update_fields or f.attname in update_fields]

        pk_val = self._get_pk_val(meta)
        if pk_val is None:
            pk_val = meta.pk.get_pk_value_on_save(self)
            setattr(self, meta.pk.attname, pk_val)
        pk_set = pk_val is not None
        if not pk_set and (force_update or update_fields):
            raise ValueError("Cannot force an update in save() with no primary key.")
        updated = False
        # If possible, try an UPDATE. If that doesn't update anything, do an INSERT.
        if pk_set and not force_insert:
            base_qs = cls._base_manager.using(using)
            values = [(f, None, (getattr(self, f.attname) if raw else f.pre_save(self, False)))
                      for f in non_pks]
            forced_update = update_fields or force_update
            updated = self._do_update(base_qs, using, pk_val, values, update_fields,
                                      forced_update)
            if force_update and not updated:
                raise DatabaseError("Forced update did not affect any rows.")
            if update_fields and not updated:
                raise DatabaseError("Save with update_fields did not affect any rows.")
        if not updated:
            if meta.order_with_respect_to:
                # If this is a model with an order_with_respect_to
                # autopopulate the _order field
                field = meta.order_with_respect_to
                order_value = cls._base_manager.using(using).filter(
                    **{field.name: getattr(self, field.attname)}).count()
                self._order = order_value

            fields = meta.local_concrete_fields
            if not pk_set:
                fields = [f for f in fields if not isinstance(f, AutoField)]

            update_pk = bool(meta.has_auto_field and not pk_set)
            result = self._do_insert(cls._base_manager, using, fields, update_pk, raw)
            if update_pk:
                setattr(self, meta.pk.attname, result)
        return updated