manager.py 文件源码

def __init__(self, *args, **kwargs):
        """Initializes a new instance of :see:PostgresManager."""

        super(PostgresManager, self).__init__(*args, **kwargs)

        # make sure our back-end is set and refuse to proceed
        # if it's not set
        db_backend = settings.DATABASES['default']['ENGINE']
        if 'psqlextra' not in db_backend:
            raise ImproperlyConfigured((
                '\'%s\' is not the \'psqlextra.backend\'. '
                'django-postgres-extra cannot function without '
                'the \'psqlextra.backend\'. Set DATABASES.ENGINE.'
            ) % db_backend)

        # hook into django signals to then trigger our own

        django.db.models.signals.post_save.connect(
            self._on_model_save, sender=self.model, weak=False)

        django.db.models.signals.pre_delete.connect(
            self._on_model_delete, sender=self.model, weak=False)

        self._signals_connected = True