【摘要】 从面向对象数据库系统中类层次的基本概念出发，讨论了对象与类的成员关系和类与类之间的交互依赖关系，提出了一种类层次模式描述语言，并讨论了将该语言表达为一阶逻辑的方法．对类层次模式中对象与类以及类与类的关系推理问题的复杂性进行了一些分析更多还原

【Abstract】 The membership relation between an object and a class and the interdependency rela-tionship among classes are discussed using some fundamental conceptions in object-orienteddatabase systems. A language CHL for describing the class hierarchy mode is proposed,which allows denoting not only primitive classes,but also classes whose extensions are ob-tained by the intersection,union or complemnet of the extensions of other classes. The for-mal description of the syntax of CHL and a method for converting this language into themonadic first-order theory is given. The complexity of hierarchy inference is analyzed.更多还原