采用ECA介体实现数据库触发器功能

封装了ECA规则的介体程序,不修改客户应用程序和数据库管理系统内核,可实现数据库触发器的事件检测、条件判断、动作执行等主动功能.其实现方式有轮询、层次化、远程过程调用等.将ECA介体引入XBase数据库,介体语言过滤器则将客户请求分离为ECA规则、过程调用和SQL命令等部分.介体同时封装了ECA规则解析器、事件检测器和动作执行器.

Realization of Functions for Database Trigger by ECA Mediator

Without modifying the client applications and the kernel of DBMS, the mediator which encapsulates ECA rules can be used to implement active functions of database trigger, such as event detection, condition evaluation and action execution etc. The practical ECA mediator includes polling, layered, RPC and so on. The ECA mediator is incorporated in Xbase, client requests are separated in ECA rules, process transfer and SQL order etc with language through filter. At same time, ECA rule parser, detector for event and executor of action is encapsulated in mediator.