Classe « MapperEvents »

Méthode sqlalchemy.orm.MapperEvents.instrument_class

Signature de la méthode instrument_class

def instrument_class(self, mapper, class_) 

Description

instrument_class.__doc__

Receive a class when the mapper is first constructed,
before instrumentation is applied to the mapped class.

.. container:: event_signatures

     Example argument forms::

        from sqlalchemy import event


        @event.listens_for(SomeClass, 'instrument_class')
        def receive_instrument_class(mapper, class_):
            "listen for the 'instrument_class' event"

            # ... (event handling logic) ...


This event is the earliest phase of mapper construction.
Most attributes of the mapper are not yet initialized.

This listener can either be applied to the :class:`_orm.Mapper`
class overall, or to any un-mapped class which serves as a base
for classes that will be mapped (using the ``propagate=True`` flag)::

    Base = declarative_base()

    @event.listens_for(Base, "instrument_class", propagate=True)
    def on_new_class(mapper, cls_):
        " ... "

:param mapper: the :class:`_orm.Mapper` which is the target
 of this event.
:param class\_: the mapped class.