Practical applications of triggers and constraints: Successes and lingering issues

Triggers are being used in a variety of significant ways in today's database systems and applications. The primary use of triggers is still to enforce various integrity constraints driven by the application, and we have argued that more uses of triggers than one might think are in fact maintaining constraints of one sort or another. Meanwhile, there is still work to do in trigger processing for researchers and developers alike, particularly to address performance issues and the lack of application development tools.