【摘要】 SDAI给应用程序提供了独立于数据存储的 STEP数据访问界面 .但是 ,SDAI的应用远没有设想中的广泛和成熟 ,原因在于基于一个真正技术成熟、应用广泛的数据存储系统 ,并且充分发挥其特色的 SDAI实现尚不多见 .通过研究 SDAI C迟联编在关系数据库系统上的实现 ,阐明了一个完整的 SDAI实现所要解决的关键技术 :模式转换、数据字典模式和 SDAI对数据库的访问策略 .更多还原

【Abstract】 SDAI provides a data access interface independent of data storage systems. Studying C late binding of SDAI on relational database system, we argue that schema translation, data dictionary schema and SDAI data access strategy are the three interrelated aspects of a complete SDAI implementation. To achieve the least loss of data semantics and efficient access of STEP data, we give emphasis on the translation of EXPRESS inheritance, organize data dictionary according to the schema translation method, and discuss three SDAI data access strategies in different application environments.更多还原