Month Year

December 2000

Issue: 17

Editor's Notes: Free VisioModeler
by Scot A. Becker

An ORM Metamodel of Barker ER
by Dr. Terry Halpin

This article provides a basic ORM metamodel for the Barker version of Entity-Relationship (ER) modeling, as discussed in Barker (1990). Traditionally used in CASE tools supported by Oracle Corporation, this notation is still one of the most widely used for ER. This article aims to clarify the Barker notation for those familiar with ORM, and also to contribute towards efforts to provide transformation between the notations. There are many ways to metamodel Barker ER, and the model discussed here is simply one suggestion.

Object-Role Modeling Wish List (Part One)
by Patrick Hallock

So far, two meta-models that involved ORM have been provided on our web site. The purpose of this was to start an open conversation about ORM and thereby gain some future model that included issues from the field. In order to keep that idea alive, I'd like to begin a series of articles; each article addressing a narrow part of ORM. The goal is go get a better product in the field. The approach should be declarative and highly productive.Part one focuses on defining objects, facts, examples, and naming. These ideas are mostly an attempt to create a faster specification to implementation approach.

Perspective and Abstraction
by Scot A. Becker

In technical literature and in the as various discussion groups, there seems to be a lot of confusion as to what is the "conceptual" level, what is the "logical" level, and what is the "physical" level. It is the author's opinion that the confusion lies in shifting meanings of the aforementioned terms. The root of this confusion illustrates the need to discuss a model in terms of two separate and orthogonal categorizations: perspective and abstraction.

Leveraging the UML Metamodel:
Expressing ORM Semantics Using a UML Profile
by David Cuyler

This paper is a proposal for a UML Profile to facilitate expression of Object Role Modeling semantics in terms of the UML 1.3 Metamodel (see http://cgi.omg.org/cgi-bin/doc?formal/00-03-01). The profile uses the extension mechanisms inherent to UML to clarify usage and semantics where necessary, and it proposes the use of the XML Metadata Interchange (XMI) specification for model exchange. Once expressed in terms of the UML Metamodel, ORM models can then be shared among UML-based tools and can be stored, managed and controlled via UML-based repositories. The paper provides an example of an ORM model fragment converted to the XMI format, in accordance with the profile.

Practical Data Administration
by Daniel Roth

In the magical land of Logical Nirvana there lives Good Queen Normalization III. In this land the Black Night Redundancy lives in shackles in the basement prison. Redundancy shares his cell with his squire Urgent Deadline. The old village of Legacy Data has been toppled and the new city of Enterprise Data has sprung up in its place. The blind alleys and dead ends have been replaced by an efficient highway system. "Because we've always done it that way!" has been erased from the city archway.

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