Further it is interesting to note that the order in which DB2 has returned the results exposes how the recursion is processed one level at a time instead of using a tree-walk .

而且，令人感兴趣的是，DB2返回结果 时所依照的顺序暴露了递归如何逐层地而不是采用 遍历 树 的 方法进行处理。