【摘要】 目前大多数软件开发都采用面向对象技术,而数据仍然保存在关系数据库中。由于对象模型和关系模型存在阻抗不匹配,因此实现对象与关系的映射已成为软件开发领域的关键问题。采用O/R M app ing(对象/关系映射)技术、XM L技术和软件分层的设计思想,实现了一个有效的数据库访问中间件,解决了利用ADO.NET开发应用程序遇到的数据表示和存取问题。更多还原

【Abstract】 Aim.To our knowledge,there does not exist object/relation(O/R) mapping middleware for ADO.NET in the open literature.We now propose such a middleware.In the full paper,we explain in detail the design of an O/R mapping middleware for ADO.NET to reduce to a minimum the notable impedance mismatch caused by object-oriented(OO) accessing of RDB(Relational DataBase).In the abstract,we just give a briefing.In designing the middleware,we adopt many techniques such as O/R mapping technique,XML and the software design concept based on layers to implement the middleware.It is composed of the three layers of object representation layer,object control layer and data access layer.The object representation layer,which represents data of objects and implements the mapping of object models and relation models,is the core part of the middleware.The object control layer controls the entity classes of the object representation layer.The data access layer encapsulates and compartmentalizes all data access code within nice and clean components that interact with RDB.The middleware we designed has a clear framework and the advantages of easy implementation,maintenance,extensibility and reuse.Our middleware has already been utilized by certain program developers who find that it helps them to reduce their accessing burden.更多还原