Designing Triggers with Trigger-By-Example

摘要

One of the obstacles that hinder database trigger systems from their wide deployment is the lack of tools that aid users in creating trigger rules. Similar to understanding and specifying database queries in SQL3, it is difficult to visualize the meaning of trigger rules. Furthermore, it is even more difficult to write trigger rules using such text-based trigger rule languages as SQL3. In this paper, we propose TBE (Trigger-By-Example) to remedy such problems in writing trigger rules visually by using QBE (Query-By-Example) ideas. TBE is a visual trigger rule composition system that helps the users understand and specify active database triggers. TBE retains benefits of QBE while extending features to support triggers. Hence, TBE is a useful tool for novice users to create simple triggers in a visual and intuitive manner. Further, since TBE is designed to hide the details of underlying trigger systems from users, it can be used as a universal trigger interface.