【摘要】 实时主动数据库的触发器中包含了各种条件,当触发器被激活时,必须对它们进行评价,如何对复杂条件进行高效的评价是系统的一个关键。本文提出了一种基于有穷自动机的状态转换图、评价优先级及路径选优法,它既实现了复杂条件的有效评价,又大大提高了评价效率,从而适应主动实时性要求。更多还原

【Abstract】 In the triggers of an real - time active database system, a variety of trigger - conditions are covered. The conditions must be evaluated when a trigger is activated. How to evaluate complex conditions efficiently, is a key for the system.This paper presents a methodology based on the final automata, including status converting graph, priorities determination and selections of optimizing paths of the evaluations. The method not only implements evaluations of the complex conditions effectively, but also enhances the evaluating efficiency so as to meet the requirements of the real - time and activity properties.更多还原