| 摘要: | 由於物件導向程式語言的興起，物件導向式系統開發愈來愈受到正視。其中設計類別圖的一致性、完整性與正確性會決定系統後續開發的成功與否。目前在結構化系統設計的實體關係模型與正規化，已有明確的設計原理及步驟；但對於物件導向的正規化尚未有完整的論述，因此本篇論文透過物件導向的封裝、繼承與多型特性，探討物件正規化的學理依據，提出物件導向第一到第四正規化的邏輯規則，並且將正規化邏輯規則具體轉換成物件導向設計類別圖塑模之七步驟，產生正規化的資料庫，並且提供具有物件導向特性的操作架構。
為了讓類別正規化研究更為完整，以結構化系統設計的實體關係圖正規化步驟為基礎，考量類別操作正規化，在第一物件正規化提出複合操作以去除功能重疊，在第二物件正規化以共用操作去除跨物件存取，在第三物件正規化提出同質操作以符合物件導向繼承與多形特性，並且在第四物件正規化加入多元相依操作作為類別屬性與操作的物件正規化邏輯。根據上述的邏輯規則，提出一套精簡、明確的設計類別正規化七步驟，作為設計類別塑模之具體方法。
綜合以上敘述，本研究提出的七步驟具體貢獻為第一步去除多值屬性、複合屬性與複合操作，第二步去除屬性的部分相依、遞移相依與共用操作，第三步去除類別之間的同質操作以符合繼承與多形特性，第四、五步建立類別以符合封裝特性，第六、七步去除多重值相依屬性與多元相依操作。在系統設計時保有物件導向特性，讓設計類別圖透過物件導向正規化七步驟建立物件正規化的實體類別與控制類別，達到一致性、完整性與正確性。
;Since the rise of object-oriented programming language, object-oriented system development get more and more attention. Consistency, completeness and correctness of the design class diagram will determine the system success or failure. Currently, entity relationship model and normalization technique for structured system design has developed clear principles and a process steps, but lack of complete discussion for object-oriented system design yet. This paper research object oreiented normalization theories through the object-oriented encapsulation, inheritance and polymorphism characteristics, proposed object-oriented principles of first to fourth normal form, and convert the principle into specific seven-step object-oriented design class diagram modeling process which will generate a normalized database, and provide a system operation architecture with object-oriented characteristics.
To complete class normalization study, considering class operation normalization based on the normalized steps of strustured system design, eliminating complex operation to prevent from overlapping functions is proposed in first object normal form. Eliminating common operation to prevent from cross-object-access operation is proposed in second object normal form. Eliminating resemble operation to meet inheritance and polymorphism characteristics is proposed in third object normal form. Eliminating multi-dependent operation to prvent from multivalued dependencies is proposed in fourth object normal form. According to above-mentioned, a clear and concise system design class modeling method is proposed.
Based on the above, the contribution are eliminating multivalue attribute, complex attribute and complex opeartion in the first step, eliminating part dependency, transitive dependency and common operation in the second step, eliminating resemble operation to meet inheritance and polymorphism characteristics in the third step, establishing Class to meet encapsulation characteristics in the fourth and fifth step, eliminating multivalue dependent attribute and multi-dependent operation in the sixth and seventh step, making system design with object-oriented characteristics, achieve consistency, completeness and correctness. |
