Mike Nicewarner

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Top Stories by Mike Nicewarner

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 is stable and closer to a shipping product than any other beta I've seen. It should be generally available by the end of February 2001. I'm using PowerDesigner version 8.0.0 build 132, the first beta release for this version. The system is a fairly stock Windows NT 4.0 system on a Pentium II 400MHz computer with 128MB of RAM. As with most modeling tools, you'll find that things go much smoother with lots of memory and a good video system. Installation and setup were fairly straightf... (more)

About Surrogate and Natural Keys

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 c... (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 the business as a way to describe data requirements at a high level. Next is the physical model used to describe the precise schema used by the database platform. Finally, there is the logical ... (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 get generational dependencies added to the mix, giving you a very powerful impact analysis. But that isn't all. PD has introduced a new type of model that links other models to each other. This is ... (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 product. Getting Started What you'll find in PD7.5 that's not in the 7.0 release: Test data generation: Complete and very functional Database size estimation: Also complete and accurate More DBMS... (more)