|Think about Loose Coupling|
DBIx::Class::Schema::Loader and on_delete/cascade_deleteby petdance (Parson)
|on Feb 15, 2012 at 17:26 UTC||Need Help??|
petdance has asked for the
wisdom of the Perl Monks concerning the following question:
I'm using 0.07017 of DBIx::Class::Schema::Loader, and I'm confused by its output for two tables with a FK relationship.
Here are excerpts of two related tables, List and Notification. Notification is a subtable of List, with a proper FK in the (Postgres) database, and it's defined as ON DELETE CASCADE in the DB. These snippets were from the files generated by ::Loader.
The DBIx::Class docs say
By default, DBIx::Class cascades deletes across has_many, has_one and might_have relationships. You can disable this behaviour on a per-relationship basis by supplying cascade_delete => 0 in the relationship attributes. The cascaded operations are performed after the requested delete, so if your database has a constraint on the relationship, it will have deleted/updated the related records or raised an exception before DBIx::Class gets to perform the cascaded operation.which I take to mean that cascade_delete should be false if the database is going to take care of the deleting for us. In this case, it will, because there's a foreign key from notification up to list with ON DELETE CASCADE. But then why is on_delete=>'CASCADE'?
It seems to me that the cascade_delete in the List.pm should be set to 1, to match the on_delete => 'CASCADE' in the Notification.pm. Or, that they should be 0 and undef, respectively. But I would think they should match.
Am I misunderstanding something? Or is DBIx::Class::Schema::Loader not building my schema correctly?