A case study of Venus and a declarative basis for rule modules

Abstract

The Venus Rule Language introduced a declarative basis for structured rule-based programming (as opposed to procedural encapsulation). The method is closely related to the nested transaction model for concurrency control and otherwise the language has been designed to serve as the basis of both main-memory and hard (or expert) activedatabase systems. We present a quantitative evaluation of the impact on development costs of the Venus language on rule-based programs. The basis of the study is a reimplementation of ALEXSYS, an active-database program originally developed in 0PS5 and currently in use in the financial securities industry. The measurements indicate substantially improved code, suggesting substantially reduced development and life-cycle costs.

Porting an expert database application to an active database

“…Essentially, we are performing the easy work during the month and holding hard wofk 1 The repofting/Iwintout modules from the expert program as reported in the companion paper [2] are ignored.…”

“…The baseline version of the ALRXSYS program is the REALESYS program as reported in the companion to this paper [2]. We will refer to it as program expert.…”

“…The companion paper [2] reports various software metrics for the REALESYS expert program vs. the ofiginal OPS5 implementation of ALEXSYS. Fof brevity reasons, these metrics are not reported for the active version.…”

“…Many of these applications inferenced over data stored in databases. One large application of this type that we have studied is the ALEXSYS mortgage pool allocator [1,2].…”