Book Image

UML 2.0 in Action: A project-based tutorial

Book Image

UML 2.0 in Action: A project-based tutorial

Overview of this book

Most books about UML describe it almost in its entirety. Inevitably you're left with only a superficial knowledge of the range of UML elements, without a deep and intuitive understanding of how to apply UML as a whole to real world design problems. This book doesn't set out to cover all of UML, but instead pulls together those parts of UML with immediate practical relevance and presents them as part of a coherent process for using UML in your actual development projects.This book is designed to be read while you work on a real project. After an initial review of the essentials of UML and the design process, it begins with the modeling of a business system and its business processes, in this case an airport. Then the IT system intended to serve that business process is described and analysed. Finally the integration of the system into the production environment is covered in detail. The book can be used in two ways: it can be read through as a thorough grounding in how UML really works in practice; in addition it can be used as stand alone guide to that particular aspect of your own project. Both result in an intuitive understanding of how to actually use UML.
Table of Contents (11 chapters)

2.2 Models, Views, and Diagrams

2.2.1 What is a Model?

Models are often built in the context of business and IT systems in order to better understand existing or future systems. However, a model never fully corresponds to reality. Modeling always means emphasizing and omitting: emphasizing essential details and omitting irrelevant ones. But what is essential and what is irrelevant? There is no universal answer to this question. Rather, the answer depends on what the goals of the model are and who is viewing or reading it.


Think about what is emphasized or omitted in the following models:

  • A wind tunnel model of a car

  • A model of a building scaled at 1:50

  • A route plan of the subway

  • A map

  • An organization chart

The more information a model is supposed to give, the more complex and difficult it becomes. A map of Europe, for example, that simultaneously contains political, geological, demographic, and transportation-related information is hardly legible. The solution to this problem is to convey the...