CREATE TRIGGER ad_projects_1
AFTER DELETE ON
    projects
FOR EACH ROW
BEGIN
    SELECT debug(
        OLD.id
    );

    DELETE FROM
        projects_tomerge
    WHERE
        project_id = OLD.id
    ;

    DELETE FROM
        updates
    WHERE
        id = (
            SELECT
                first_update_id
            FROM
                topics
            WHERE
                id = OLD.id
        )
    ;

END;