Method selectinload

lib/sqlalchemy/orm/strategy_options.py:358–418

Indicate that the given attribute should be loaded using SELECT IN eager loading. This function is part of the :class:`_orm.Load` interface and supports both method-chained and standalone operation. examples:: # selectin-load the "orders" collection on

(
        self,
        attr: _AttrType,
        recursion_depth: Optional[int] = None,
        chunksize: Optional[int] = None,
    )

        return self._set_relationship_strategy(attr, {"lazy": "subquery"})

    def selectinload(
        self,
        attr: _AttrType,
        recursion_depth: Optional[int] = None,
        chunksize: Optional[int] = None,
    ) -> Self:
        """Indicate that the given attribute should be loaded using
        SELECT IN eager loading.

        This function is part of the :class:`_orm.Load` interface and supports
        both method-chained and standalone operation.

        examples::

            # selectin-load the "orders" collection on "User"
            select(User).options(selectinload(User.orders))

            # selectin-load Order.items and then Item.keywords
            select(Order).options(
                selectinload(Order.items).selectinload(Item.keywords)
            )

            # lazily load Order.items, but when Items are loaded,
            # selectin-load the keywords collection
            select(Order).options(lazyload(Order.items).selectinload(Item.keywords))

        :param recursion_depth: optional int; when set to a positive integer
         in conjunction with a self-referential relationship,
         indicates "selectin" loading will continue that many levels deep
         automatically until no items are found.

         .. note:: The :paramref:`_orm.selectinload.recursion_depth` option
            currently supports only self-referential relationships.  There
            is not yet an option to automatically traverse recursive structures
            with more than one relationship involved.

            Additionally, the :paramref:`_orm.selectinload.recursion_depth`
            parameter is new and experimental and should be treated as "alpha"
            status for the 2.0 series.

         .. versionadded:: 2.0 added
            :paramref:`_orm.selectinload.recursion_depth`

        :param chunksize: optional int; when set to a positive non-zero
         integer, the keys from the IN statement will be chunked relative
         to the passed parameter

         .. versionadded:: 2.1.0b3

        .. seealso::

            :ref:`loading_toplevel`

            :ref:`selectin_eager_loading`

        """
        return self._set_relationship_strategy(
            attr,