一個關連式資料庫的物件界面元件產生器

Abstract

關連式資料庫管理系統乃當今商業資訊系統之主要資料儲存與管理系統。另一方面，物件導向技術則已成為大型軟體開發之主流方法。為關連式資料庫提供一組物件界面，可以為資料庫應用程式的開發帶來一些物件科技的優點。然而為關連式資料庫提供物件界面，一向被認為是一件耗費時間且又容易出錯的工作。在本篇論文裡，我們提出一個稱為「資料庫存取元件產生器(DACG)」的架構，可以用來消除建立資料庫物件界面所需的程式工作。DACG有兩個主要優點：一、它是一個「免寫程式」的架構，DACG的使用者可以不需要寫一行程式便可產生資料庫的物件界面。二、DACG產生的元件有很好的可重複使用性，它們可以被多種程式語言的發展環境裡所使用。DACG的核心是一個以應用架構（Application Framework）為基礎的程式碼產生器。DACG採用「元件導向軟體工程」的方法來縮短發展的時程，其下層的元件模型則是微軟的Component Object Model (COM)，因此它可以用任何支援COM的物件語言來實作。本篇論文同時也呈現一個DACG的實作系統，我們選擇的程式語言是Visual Basic，後端的資料庫系統則是Microsoft SQL Server。此外，本篇論文最後也以一Web應用程式－「線上徵才系統」為例，展示了DACG Component的實際應用。

The Relational Database Management Systems (RDBMS) is the dominant data management technology of today’s business information system. Meanwhile, object-oriented methodology has become the mainstream approach of building large-scale software applications. Providing an object-based abstraction of database access can bring the advantages of object technology to the database-intensive applications. However, it is known that providing object interfaces of RDBs is very time-consuming and error-prone, and usually the object interfaces cannot be reused. In this paper, we propose an architecture called “Data Access Component Generator (DACG)” to eliminate the programming efforts of the data object interfacing task. DACG has two major advantages. First, it is a code-free architecture; the user of DACG can build data interfaces without writing any source code. Second, the data interfaces have great reusability; they can be reused in several programming languages. The kernel of DACG is a framework-based code generator. DACG adopt the Component-Based Software Engineering (CBSE) to shorten its development cycle. The underlying component model of DACG uses the Microsoft’s Component Object Model (COM). Therefore it can be implemented in any COM-complied language. A DACG implementation with Microsoft SQL Server as the backend DBMS is also presented. Visual Basic Application version (VBA) was chosen as the programming language to implement our system. Moreover, this research has demonstrates the usage of DACG components by applying it to achieve the database-to-www bridging in real world web applications.