CREATE TRIGGER ai_task_status_1
AFTER INSERT ON
    task_status
FOR EACH ROW WHEN
    NEW.def = 1
BEGIN

    SELECT debug(
        NEW.id,
        NEW.project_id,
        NEW.status
    );

    UPDATE
        task_status
    SET
        def = NULL
    WHERE
        project_id = NEW.project_id AND
        def = 1 AND
        id != NEW.id
    ;

END;