Read me first!

If you are like me, you usually skip book introductions and jump straight into Chapter 1. By calling this section “Read me First” instead of “Introduction”, I am hoping you will actually read this first. It will help you get the most out of this book by becoming familiar with the learning objectives and getting a glimpse of each section and chapter. You will also find out the meaning of the icons we’ve splashed liberally across the book – I’m sure you can guess most of them yourself, but good data modelers must ensure their meaning is clearly communicated to their audience.

This book has ten key objectives for you, the reader:

1.      You will know when a data model is needed and which PowerDesigner models are the most appropriate for each situation

2.      You will be able to read a data model of any size and complexity with the same confidence as reading a book

3.      You will know when to apply and how to make use of all the key features of PowerDesigner

4.      You will be able to build, step-by-step in PowerDesigner, a pyramid of linked data models, including a conceptual data model, a fully normalized relational data model, a physical data model, and an easily navigable dimensional model

5.      You will be able to apply techniques such as indexing, transforms, and forward engineering to turn a logical data model into an efficient physical design

6.      You will improve data governance and modeling consistency within your organization by leveraging features such as PowerDesigner’s reference models, Glossary, domains, and model comparison and model mapping techniques

7.      You will know how to utilize dependencies and traceability links to assess the impact of change

8.      You will know how to integrate your PowerDesigner models with externally-managed files, including the import and export of data using Excel® and Requirements documents

9.      You will know where you can take advantage of the entire PowerDesigner model set, to increase the success rate of corporate-wide initiatives such as business intelligence and enterprise resource planning (ERP)

10.  You will understand the key differentiators between PowerDesigner and other data modeling tools you may have used before

This book contains seven sections:

Section I introduces data modeling, along with its purpose and variations.

Section II explains all of the components on a data model including entities, data elements, relationships, and keys. Also included is a discussion of the importance of quality names and definitions for your objects.

Section III explains the important role of data modeling tools, the key features required of any data modeling tool, and an introduction to the essential features of PowerDesigner. It also describes how to create and manage data modeling objects in PowerDesigner.

Section IV introduces the Data Model Pyramid, then dives into the relational and dimensional subject areas, logical, and physical data models, and describes how PowerDesigner supports these models and the connections between them.

Section V guides you through the creation of your own Data Model Pyramid.

Section VI focuses on additional PowerDesigner features (some of which have already been introduced) that make life easier for data modelers. Learn how to get information into and out of PowerDesigner, and improve the quality of your data models with a cross-reference of key PowerDesigner features with the Data Model Scorecard®.

Section VII discusses PowerDesigner topics beyond data modeling, including the XML physical model and the other types of model available in PowerDesigner.

To connect the book’s content with the book’s key objectives stated on the previous page: the following table shows the key sections that support each objective.

Key points are included at the end of each chapter as a way to reinforce concepts. All of the key points are also summarized at the end of the text. Every chapter starts with a poem in the form of a haiku, which is a three-line poem containing five syllables in the first line, seven in the second, and five in the third.

As we introduce you to new PowerDesigner features, we use ‘Your Turn’ sessions to familiarize you with them. At the end of most chapters there are thought-provoking exercises, with answers provided in the Appendix. Also at the back of the book are two handy glossaries, a quick-reference guide to PowerDesigner, and a comprehensive index.

How to get the Most out of this Book

It is not possible to show you how to use all of PowerDesigner’s features in the space available, so we tell you what features there are, introduce to you them, and refer you to the comprehensive PowerDesigner documentation for more information. Some features are especially important for all PowerDesigner users, or for data modelers in particular, so please bear with us, even if the detail is excruciating. There is always an end in sight. For the same reason, we may even repeat ourselves several times. In some areas, you may wish for more detail; sorry but this is not a PowerDesigner training manual.

It’s important to know what you can expect to learn from a book, and it’s equally important to know what you will NOT learn from a book. We make no attempt here to teach database design or SQL; PowerDesigner supports many different relational technologies as well as XML schemas, and it would take a much larger book to explain how best to utilize that support.

Icons Used in this Book

This book uses icons to focus your attention on PowerDesigner topics, helping you to identify what’s really important to you.

Conventions Used in this Book

As you work through the book, you will see references to objects and symbols in data models, keys on the keyboard, and parts of the PowerDesigner environment, such as items on PowerDesigner menus, tools on the palette, and dialog buttons.

Sometimes we just enclose an entry in single quotes (like ‘G’) where the context makes it obvious what we mean. Otherwise, we make use of the following simple conventions.

In Summary

PowerDesigner is a complex tool, providing support for a multitude of possible approaches. Sybase does not restrict you to any given methodology. We describe a methodology in this book, show you how to make it work in PowerDesigner, and describe some potential strategies for using PowerDesigner. By the way, every diagram in this book (except the cartoons and the pyramid in Section IV) was produced in PowerDesigner.

Data modeling is more than a job or a career - it is a mindset, an invaluable process, a healthy addiction, a way of life. Remember to Keep It Simple, and enjoy the ride!