Method after_mapper_constructed

lib/sqlalchemy/orm/events.py:945–977

Receive a class and mapper when the :class:`_orm.Mapper` has been fully constructed. This event is called after the initial constructor for :class:`_orm.Mapper` completes. This occurs after the :meth:`_orm.MapperEvents.instrument_class` event and after the :

(
        self, mapper: Mapper[_O], class_: Type[_O]
    )

        """

    def after_mapper_constructed(
        self, mapper: Mapper[_O], class_: Type[_O]
    ) -> None:
        """Receive a class and mapper when the :class:`_orm.Mapper` has been
        fully constructed.

        This event is called after the initial constructor for
        :class:`_orm.Mapper` completes.  This occurs after the
        :meth:`_orm.MapperEvents.instrument_class` event and after the
        :class:`_orm.Mapper` has done an initial pass of its arguments
        to generate its collection of :class:`_orm.MapperProperty` objects,
        which are accessible via the :meth:`_orm.Mapper.get_property`
        method and the :attr:`_orm.Mapper.iterate_properties` attribute.

        This event differs from the
        :meth:`_orm.MapperEvents.before_mapper_configured` event in that it
        is invoked within the constructor for :class:`_orm.Mapper`, rather
        than within the :meth:`_orm.registry.configure` process.   Currently,
        this event is the only one which is appropriate for handlers that
        wish to create additional mapped classes in response to the
        construction of this :class:`_orm.Mapper`, which will be part of the
        same configure step when :meth:`_orm.registry.configure` next runs.

        .. versionadded:: 2.0.2

        .. seealso::

            :ref:`examples_versioning` - an example which illustrates the use
            of the :meth:`_orm.MapperEvents.before_mapper_configured`
            event to create new mappers to record change-audit histories on
            objects.

        """

    @event._omit_standard_example
    def before_mapper_configured(