signals or triggers in SQLAlchemy

Question

does SQLAlchemy have something similar to Django\'s signal concept? Basically, I\'d like to trigger a few functions when I pre-save or post-save some entity objects. Thanks.

Answer 1

You can use inner MapperExtension class:

class YourModel(db.Model):

    class BaseExtension(MapperExtension):

        def before_insert(self, mapper, connection, instance):
            # do something here

        def before_update(self, mapper, connection, instance):
            # do something here

    __mapper_args__ = { 'extension': BaseExtension() }

    # ....