Mike Nicewarner

The purpose of this article is to discuss and describe the terms "Surrogate Key" and "Natural Key," and explain when they are appropriate to use in a data model. Furthermore, the concepts of "Intelligence" and "Generated" will be applied to both types of keys. The goal is for the reader to understand the plusses and minuses of all forms of identifying records uniquely in a database system. The reader is also challenged to think critically about the business situation before adopting any given identification methodology. Terms Defined Surrogate Key A surrogate key is a column or columns that are not defined by business requirements, but are added to a table simply to identify records uniquely. For example, a business might define a set of related attributes that it wants... (more)

Sybase PowerDesigner: Impact Analysis

Sybase has recently included impact analysis features into the PowerDesigner (PD) modeling tool. If you aren't familiar with PD, it's a powerful tool for modeling business processes, data designs, XML messages, and application logic (ala UML). Within each model, you can view the dependent objects (basically, what would be affected if you deleted something). By using the repository, you ge... (more)

PowerDesigner 8.0 Beta

PowerDesigner is a very good data modeling tool, but with UML gaining acceptance in many IT shops, Sybase has gradually added object modeling features. In November, they started another beta program named Beluga primarily to add Use Case and Sequence diagrams, but also to fix some problems with packages and enhance the overall user interface. As with previous PowerDesigner betas, Beluga ... (more)

PowerDesigner 7.5 Beta Review by Sybase

Although still in beta, version 7.5 of the PowerDesigner Suite (PD7.5) from Sybase is a stable product. As the fifth iteration of the Dolphin code rewrite, it's mature and highly functional. To examine what PD7.5 looks like, let's walk through it. I like conceptual modeling, so this is where I usually begin. I'm using PowerDesigner version 7.5.0 build 715, the second beta release of the ... (more)

Why Have Conceptual, Logical, and Physical Data Modeling?

Many modelers are confused by overlaps in the data modeling terminology from the various vendors, and are not sure how to compare modeling tools when trying to buy one. This article will attempt to shed some light on this topic, and hopefully answer some of the more frustrating questions. With data modeling, there are three models to deal with. First is the conceptual model, geared toward... (more)