CREATE TRIGGER bu_project_related_updates
BEFORE UPDATE OF
    merkled
ON
    project_related_updates
FOR EACH ROW WHEN
    NEW.merkled = 1
BEGIN
    SELECT debug(
        'bu_project_related_updates',
        NEW.project_id,
        NEW.update_id,
        NEW.merkled
    );

    INSERT INTO
        projects_merkle(
            project_id,
            prefix,
            hash,
            num_updates
        )
    SELECT
        NEW.project_id,
        src.prefix,
        substr(agg_sha1_hex(src.uuid, src.uuid),1,8) AS hash,
        count(src.uuid) as num_updates
    FROM
        (
        SELECT
            u2.prefix,
            u2.uuid
        FROM
            updates u
        INNER JOIN
            updates u2
        ON
            u2.prefix = u.prefix
        INNER JOIN
            project_related_updates pru
        ON
            pru.update_id = u2.id AND pru.project_id = NEW.project_id
        WHERE
            u.id = NEW.update_id
        ) src
    GROUP BY
        NEW.project_id,
        src.prefix
    ;

END;