attribute collection的用法和樣例：
例句
- This sets the extended attribute value of the file.
這樣可以設置文件的擴展屬性集。 - Since conditional attribute set has been an algebraic consistent set, it can guarantee to obtain a reduction by top-bottom strategy to eliminate reducible attributes.
由于所有條件屬性集已是一個(gè)代數協(xié)調集，采用自頂而下逐步刪除可約屬性的策略，提出一種基于數據庫系統求代數約簡(jiǎn)的算法。
