【摘要】 “可互操作的面向对象数据库平台MODIP系统”采用了两级式的客户机/服务器体系结构,完成了多个异构数据源上的互操作。系统提供了互操作查询语言IOQL来实现多数据源上的查询。文中讨论了系统中IOQL的实现。IOQL是ODMG中OQL语言的扩展。IOQL可以在命令行形式下执行,也可采用嵌入式的方式在编程语言中执行。文中还介绍了IOQL的执行过程及其优化,主要针对对象管理器提供的接口的特点。对查询语句进行重写,以期达到更高执行效率。更多还原

【Abstract】 MODIP(Multiple Object-oriented Databases Interoperable Platform), which supports the interoperation between heterogenenous databases, uses two-level client / server architecture. It provides IOQL(Interoperable Object Query Language) which enables users to manipulate data in multiple databases. This paper presents the implemention details of IOQL in MODIP.IOQL is an extension of the standard OQL in ODMG.IOQL query can be executed under command line. Embedded IOQL in programming languages is also available. Besides, we give the execution process and query optimization of IOQL. The queries are rewritten according to the interface given by the object management module to achieve higher execution efficiency.更多还原