Classe « SessionEvents »

Méthode sqlalchemy.orm.SessionEvents.before_attach

Signature de la méthode before_attach

def before_attach(self, session, instance) 

Description

before_attach.__doc__

Execute before an instance is attached to a session.

.. container:: event_signatures

     Example argument forms::

        from sqlalchemy import event


        @event.listens_for(SomeSessionOrFactory, 'before_attach')
        def receive_before_attach(session, instance):
            "listen for the 'before_attach' event"

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


This is called before an add, delete or merge causes
the object to be part of the session.

.. seealso::

    :meth:`~.SessionEvents.after_attach`

    :ref:`session_lifecycle_events`