Method raiseload

lib/sqlalchemy/orm/strategy_options.py:504–540

Indicate that the given attribute should raise an error if accessed. A relationship attribute configured with :func:`_orm.raiseload` will raise an :exc:`~sqlalchemy.exc.InvalidRequestError` upon access. The typical way this is useful is when an application is attempting to

(self, attr: _AttrType, sql_only: bool = False)

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

    def raiseload(self, attr: _AttrType, sql_only: bool = False) -> Self:
        """Indicate that the given attribute should raise an error if accessed.

        A relationship attribute configured with :func:`_orm.raiseload` will
        raise an :exc:`~sqlalchemy.exc.InvalidRequestError` upon access. The
        typical way this is useful is when an application is attempting to
        ensure that all relationship attributes that are accessed in a
        particular context would have been already loaded via eager loading.
        Instead of having to read through SQL logs to ensure lazy loads aren't
        occurring, this strategy will cause them to raise immediately.

        :func:`_orm.raiseload` applies to :func:`_orm.relationship` attributes
        only. In order to apply raise-on-SQL behavior to a column-based
        attribute, use the :paramref:`.orm.defer.raiseload` parameter on the
        :func:`.defer` loader option.

        :param sql_only: if True, raise only if the lazy load would emit SQL,
         but not if it is only checking the identity map, or determining that
         the related value should just be None due to missing keys. When False,
         the strategy will raise for all varieties of relationship loading.

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

        .. seealso::

            :ref:`loading_toplevel`

            :ref:`prevent_lazy_with_raiseload`

            :ref:`orm_queryguide_deferred_raiseload`

        """

        return self._set_relationship_strategy(
            attr, {"lazy": "raise_on_sql" if sql_only else "raise"}
        )

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