Method bulk_insert_mappings

lib/sqlalchemy/orm/session.py:4762–4843

Perform a bulk insert of the given list of mapping dictionaries. .. legacy:: This method is a legacy feature as of the 2.0 series of SQLAlchemy. For modern bulk INSERT and UPDATE, see the sections :ref:`orm_queryguide_bulk_insert` and :ref:

(
        self,
        mapper: _EntityBindKey[Any],
        mappings: Iterable[Dict[str, Any]],
        return_defaults: bool = False,
        render_nulls: bool = False,
    )

            )

    def bulk_insert_mappings(
        self,
        mapper: _EntityBindKey[Any],
        mappings: Iterable[Dict[str, Any]],
        return_defaults: bool = False,
        render_nulls: bool = False,
    ) -> None:
        """Perform a bulk insert of the given list of mapping dictionaries.

        .. legacy::

            This method is a legacy feature as of the 2.0 series of
            SQLAlchemy.   For modern bulk INSERT and UPDATE, see
            the sections :ref:`orm_queryguide_bulk_insert` and
            :ref:`orm_queryguide_bulk_update`.  The 2.0 API shares
            implementation details with this method and adds new features
            as well.

        :param mapper: a mapped class, or the actual :class:`_orm.Mapper`
         object,
         representing the single kind of object represented within the mapping
         list.

        :param mappings: a sequence of dictionaries, each one containing the
         state of the mapped row to be inserted, in terms of the attribute
         names on the mapped class.   If the mapping refers to multiple tables,
         such as a joined-inheritance mapping, each dictionary must contain all
         keys to be populated into all tables.

        :param return_defaults: when True, the INSERT process will be altered
         to ensure that newly generated primary key values will be fetched.
         The rationale for this parameter is typically to enable
         :ref:`Joined Table Inheritance <joined_inheritance>` mappings to
         be bulk inserted.

         .. note:: for backends that don&#x27;t support RETURNING, the
            :paramref:`_orm.Session.bulk_insert_mappings.return_defaults`
            parameter can significantly decrease performance as INSERT
            statements can no longer be batched.   See
            :ref:`engine_insertmanyvalues`
            for background on which backends are affected.

        :param render_nulls: When True, a value of ``None`` will result
         in a NULL value being included in the INSERT statement, rather
         than the column being omitted from the INSERT.   This allows all
         the rows being INSERTed to have the identical set of columns which
         allows the full set of rows to be batched to the DBAPI.  Normally,
         each column-set that contains a different combination of NULL values
         than the previous row must omit a different series of columns from
         the rendered INSERT statement, which means it must be emitted as a
         separate statement.   By passing this flag, the full set of rows
         are guaranteed to be batchable into one batch; the cost however is
         that server-side defaults which are invoked by an omitted column will
         be skipped, so care must be taken to ensure that these are not
         necessary.

         .. warning::