CREATE TRIGGER ai_hubs_merkle2
AFTER INSERT ON
    hubs_merkle
FOR EACH ROW WHEN
    NEW.num_updates = 0
BEGIN
    SELECT debug(
        'ai_hubs_merkle2',
        NEW.hub_id,
        NEW.prefix,
        NEW.hash,
        NEW.num_updates
    );

    DELETE FROM
        hubs_merkle
    WHERE
        hub_id = NEW.hub_id AND prefix = NEW.prefix
    ;
END;