主动数据库中的时序逻辑

ECA主动规则中的“条件”通常描述主动数据库的当前状态或状态转换,表现为一个或一组查询语句。但是经常还会遇到基于数据库一系列状态演变过程之上的查询要求,这时不能使用平常意义上的条件来表示。文章基于过去时序逻辑,提出了一种说明时序条件的语言,可以对数据库基于时间状态的演变的过程进行监控,从而增强了主动数据库中规则语言的表达能力。

Analysis of Termination of Active Rules with Compotive Events

ECA rule has been widely accepted as the supporting mechnism in active database systems which provide active services.The problem of termination of an ECA rule base has attratced many interests.Based on a formal descrip-tion of the semantics of ECA rules,this paper investigates into the potential influence that composite events may bring to the analysis of termination.A static decisive algorithm supporting composite event mechnism is given,which differs from any of the formed related work.As pointed out ,this algorithm can work as the theoretical base of static analysis tools for active rule systems.