级联触发器终止性的实现  

Implementation of cascaded triggers termination

作　　者：邓晓军[1] 

机构地区：[1]湖南冶金职业技术学院,湖南株洲412000

出　　处：《计算机工程与设计》2006年第15期2882-2883,2908,共3页Computer Engineering and Design

摘　　要：通过给出触发器的形式描述,对级联触发器的终止性进行详细探讨,并分析了大型商用数据库系统终止级联触发器的方法。提出了一种避免级联触发器无限循环的方法,即采用限制触发器循环执行次数,并结合级联触发器上限参数,可以允许某些循环级联触发器的正常执行,同时又能有效地保证级联触发器的终止性。这种方法已在GKD国产数据库系统中得到应用和实现。Describing through the formal of triggers, the termination of cascaded triggers is discussed, and the method of the termination cascaded triggers in commercial database system is analysed. Cascaded triggers may cause infinite loop in the running process. A method which can avoid the infinite loop of cascaded triggers and solves the problem in two ways is presented. While limiting the cycle counts of running triggers and setting upper limit of cascaded levels of triggers, cascaded triggers to run in loop is admited, and running infinitely is prevent at the same time. This method has been implemented in a native database system named GKD.

关 键 词：数据库系统 级联触发器 “事件-条件-动作”规则 终止性 跟踪链 

分 类 号：TP311.13[自动化与计算机技术—计算机软件与理论]