基于自依赖规则分析的主动规则终止性研究

Research of active rules termination based on self-dependent rules analysis

ECA规则终止性问题是主动数据库中一个关键问题,首先分析触发边、活化边、惰化边三种边的触发时序关系;然后构造条件断言函数来描述活化边和惰化边对ECA规则中条件的影响,总结出了触发边、活化边和惰化边的组合时序对规则的具体触发情况;最后在此基础上进一步完善了BarakisR提出的不可归约规则集中的自依赖规则判定算法,对其中能够形成环状结构的自触发规则进行了全面的讨论,提出一种新的自依赖规则判定算法。该算法首先找到在不可归约集中由自触发规则引发的循环触发,然后对自触发规则进行单独处理来打断这个环从而使规则集终止,有效提高了规则终止性问题的判断能力。

ECA rules termination is a key problem in ACDB. Firstly, triggering time sequence about triggering edge, activation edge and deactivation edge is analyzed. Secondly, condition asseveration function is constructed to illustrate the effect of activation edge and deactivation edge on ECA rules. Combination time sequence of Triggering edge, detriggering edge and activation edge are proposed to an- alyze triggering in ECA. Finally, Self-dependent rules judgment algorithm in irreducible rule set, which is proposed by Barakis R, is improved further, Self- triggering rules that cause cyclic structure are dis- cussed deeply, and a new self--dependent rules judgment algorithm is proposed. The algorithm can find cyclic triggering in irreducible rule set, then self--triggering rules are independently processed so as to interrupt the triggering ring, hence efficiently improving the judgment ability of active rules termination problem.