ordered subset造句

An index is an ordered subset of the table on which it is created
索引是创建索引所基于的表的有序子集。
To alter the arrangement of a set of items from two or more ordered subsets to one or more other subsets each containing a number of items , commonly one , from each of the original subsets in a specified order that is not necessarily the order of any of the original subsets
将两个或多个有序子集中项目集合的排列按所指明的顺序改变成一个或多个子集，每个子集包含若干个（通常为一个）来自每个原先子集中的项目，但不一定和任何原先子集中的排序一样。
It's difficult to find ordered subset in a sentence. 用ordered subset造句挺难的