Month Year

August 1998

Issue: 4

Editor's Notes: GUIe
by Scot A. Becker

UML Data Models from an ORM Perspective (Part 4)
by Dr. Terry Halpin

This paper is the fourth in a series of articles examining data modeling in the Unified Modeling Language (UML) from the perspective of Object Role Modeling (ORM). Part 1 provided historical background and design criteria for modeling languages, and discussed object reference and single-valued attributes. Part 2 discussed multi-valued attributes, basic constraints, and instantiation using UML object diagrams or ORM fact tables. Part 3 compared UML associations and related multiplicity constraints with ORM relationship types and related uniqueness, mandatory role and frequency constraints; it also contrasted instantiation of associations using UML object diagrams and ORM fact tables. In Part 4 we look at associations in more detail, contrasting ORM nesting with UML association classes, and ORM co-referencing with UML qualified associations, then discuss exclusion constraints, and summarize how the two methods compare with respect to terms and notations for data structures and instances.

Normalization and ORM
by Scot A. Becker

There has to be a better way to do this. In fact there is, but you don't see it talked about very often (except in pioneering publications such as this, of course!). And that (Object-Role Modeling, or ORM) is my main focus for this article.

De-Normalization and Keeping Up With the Constraints
by Pat Hallock

About the time we get most people understanding normalization and the advantages of doing so, we run into the new rage to create de-normalized models. It's sometimes important to point out that "to de-normalize" really means it was first "normalized". The process of de-normalization should not take the place of an initial normalized model.

Is it still a requirement if the subject matter expert
didn't tell the analyst?
by Dr. John K. Sharp

Most information technology projects start with an incomplete and possibly inconsistent problem statement generated by the subject matter expert or an involved manager. The subject matter expert and the manger know a lot about the process(es) being analyzed, but they do not know what is needed by the information analyst to provide for the creation of the supporting application.

Conceptual Level Information System
Implementation in Prolog
by Dennis Corbo

One of the ongoing challenges in the development of information systems is the translation of a conceptual model into an implementation of the model. This article will attempt to show the correlation between a conceptual model represented as an Object Role Model (ORM) and the model implemented in Prolog. The main purpose is to demonstrate that much of the conceptual nature of an ORM is not necessarily lost when implemented as a working information system. Practically speaking, a close correlation between a model and a model’s implementation makes it very feasible and attractive to use the model for maintenance of the system.

Dr. John Sharp
Analysis Problem
Solution for Last Issue's Analysis Problem