KiokuDB::Role::Upgrade::Data - Classes that provide their own upgrade routine.

    with qw(KiokuDB::Role::Upgrade::Data);

    sub kiokudb_upgrade_data {
        my ( $class, %args ) = @_;

        # convert the data from the old version of the class to the new version
        # as necessary

        $args{entry}->derive(
            class_version => our $VERSION,
            ...
        );
    }

This class allows you to take control the data conversion process completely (there is only one handler per class, not one handler per version with this approach).

See KiokuDB::Role::Upgrade::Handlers::Table for a more DWIM approach, and KiokuDB::TypeMap::Entry::MOP for more details.