臺灣博碩士論文加值系統

我們提出一個物件導向式資料模型, 這個資料模型包含一個類別代數。這
個代數在聯集, 交集, 差集, 選擇, 投射, 組合等運算下是個封閉的模型
。這封閉性是指任何集合的運算式都有一個良好定義(well-defined)的集
合, 這集合中的元素都具有一個由一些被要求的屬性所成的集合, 這些被
要求的屬性都有良好定義的領域, 而且每個元素也都滿足一個良好定義的
不變量(invariant) 。因此, 每一個類別都有一個由 ISA 父類別(
parent classes) 所組成的明確集合, 和一個由繼承來的資料項和程序
項 (slots and Methods) 所組成的明確集合; 每一資料項和程序項也都
有良好定義的領域。我們模型主要的優點是自動分類包含這些代數在聯
集, 交集, 差集, 選擇, 投射, 組合等運算所獲得的結果。也就是說, 這
集合運算式被搬到 ISA 架構中的正確位置決定於由這運算式計算得來的
不變量。

We present an object-oriented data model which includes an
algebra of classes that is closed under the operations of
union, intersection, difference, selection, projection, and
join. The closure property means that any set expression has a
well- defined set of elements with a specific set of required
attributes with well-defined domains, and which satisfy a well-
defined invariant. Therefore, each class also has a definite
set of ISA parent classes, ISA subclasses and inherited slots
and methods with well-defined domains. The involving the
union, intersection, difference, select, project, and join
operators. That is, the set expression is moved into its
correct location in the ISA hierarchy, depending on the
invariant which is computed for that expression.