Method defaultload

lib/sqlalchemy/orm/strategy_options.py:542–579

Indicate an attribute should load using its predefined loader style. The behavior of this loading option is to not change the current loading style of the attribute, meaning that the previously configured one is used or, if no previous style was selected, the default

(self, attr: _AttrType)

        )

    def defaultload(self, attr: _AttrType) -> Self:
        """Indicate an attribute should load using its predefined loader style.

        The behavior of this loading option is to not change the current
        loading style of the attribute, meaning that the previously configured
        one is used or, if no previous style was selected, the default
        loading will be used.

        This method is used to link to other loader options further into
        a chain of attributes without altering the loader style of the links
        along the chain.  For example, to set joined eager loading for an
        element of an element::

            session.query(MyClass).options(
                defaultload(MyClass.someattribute).joinedload(
                    MyOtherClass.someotherattribute
                )
            )

        :func:`.defaultload` is also useful for setting column-level options on
        a related class, namely that of :func:`.defer` and :func:`.undefer`::

            session.scalars(
                select(MyClass).options(
                    defaultload(MyClass.someattribute)
                    .defer("some_column")
                    .undefer("some_other_column")
                )
            )

        .. seealso::

            :ref:`orm_queryguide_relationship_sub_options`

            :meth:`_orm.Load.options`

        """
        return self._set_relationship_strategy(attr, None)

    def defer(self, key: _AttrType, raiseload: bool = False) -> Self:
        r"""Indicate that the given column-oriented attribute should be