On the one hand , it requires dbms provide a security strategy to make sure of data to be used safely ; on the other hand , because of client / server technology developing and consummating , dbms often runs on background server , which security is provided by itself . but client application runs on client , its security can but is designed by application programmer , which is used to prevent users which have no access from executing program model 一方面,這就要求數據庫管理系統必須能夠提供一種安全基礎為用戶保證數據的安全使用;另一方面,由于客戶服務器技術的日益發展和完善,數據庫管理系統通常運行在后臺的服務器上,其安全性由其本身提供,但業務系統位于客戶端,其安全性的維護只能由系統開發人員自行設計,主要是用來防止未授權用戶對程序模塊的非法執行。
For resolving the problem mentioned above . the paper gives out a robust persistence layer that maps objects to persistence mechanisms in such a manner that simple changes to the relational schema do not affect your object - oriented code . because there is a mapping dictionary in the persistence layer . the advantage of this approach is that your application programmers do not need to know a thing about the schema of the relational database 為了解決上述問題,本文提出:在對象與關系數據庫之間建立映射機制來消除面向對象模型與關系數據庫不匹配;將sql代碼封裝在持久層中,同時在持久層中建立映射字典,通過字典來動態組裝sql語句,從而使得對象模型與關系數據庫之間的具有無關性,即數據庫模式的改變,不影響對象模型;對象模型的改變不影響數據庫模式。
Mom hides the details of network communication , and presents an api for application programmers to facilitate message exchange in an asynchronous and secure style . furthermore , it achieves loosely couple between client and server via message queue . mom is put into practice to develop enterprise scale three - tier ( or more ) client / server applications 本系統屏蔽了客戶機服務器模式中的網絡通信細節,給用戶提供了簡單方便的應用程序接口,實現了低可靠性網絡通信的異步性和安全性,具有可移植性和可伸縮性,適用于企業級三層或多層客戶機服務器應用程序的開發。