[...]... Summary 496 Chapter 17 Enterprise Data Models and Data Management 17.1 Introduction 499 17.2 Data Management 17.2.1 17.2.2 17.2.3 500 Problems of Data Mismanagement 500 Managing Data as a Shared Resource 501 The Evolution of Data Management 501 17.3 Classification of Existing Data 17.4 A Target for Planning 503 504 17.5 A Context for Specifying New Databases 17.5.1 17.5.2 17.6 Guidance for Database... programs that capture, store, manipulate, and retrieve the data (Figure 1.1) These programs are designed to implement a process model (or functional specification), specifying the business processes that the system is 3 4 ■ Chapter 1 What Is Data Modeling? Report Report Program Program data data DATABASE data Program data data Program Figure 1.1 Program An information system to perform In the same way,... relational database, and we could give this model to a database administrator as a specification of what to build, just as an architect gives a plan to a builder We have shown a few rows of data for illustration; in practice the database might contain thousands or millions of rows in the same format Data models can be presented in many different ways In this case we have taken the unusual step of including... the database is specified by a data model, describing what sort of data will be held and how it will be organized 1.3 A Simple Example Before going any further, let’s look at a simple data model.1 Figure 1.2 shows some of the data needed to support an insurance system We can see a few things straightaway: ■ 1 The data is organized into simple tables This is exactly how data is organized in a relational... design in a set of data models In this chapter, we address some fundamental questions: ■ ■ ■ ■ ■ ■ ■ ■ What is a data model? Why is data modeling so important? What makes a good data model? Where does data modeling fit in systems development? What are the key design stages and deliverables? How does data modeling relate to database performance design? Who is involved in data modeling? What is the impact... deeper appreciation of the process Specialist data modelers, database designers, and database administrators will want to read Parts I and II in their entirety, and at least refer to Part III as necessary Nonspecialists who find themselves in charge of the data modeling component of a project will need to do the same; even “simple” data models for commercial applications need to be developed in a disciplined... and vigorous challenges Organization The book is in three parts Part I covers the basics of data modeling It introduces the concepts of data modeling in a sequence that Graham and I have found effective in teaching data modeling to practitioners and students over many years 1 Simsion, G.C.: Data Modeling — Testing the Foundations,” Database Programming and Design, (February 1996.) Preface ■ xxv Part... practice, as supported by leading modeling tools and database management systems, and the advice takes into account the realities of developing systems in a business setting It is gratifying to see that this practical focus has not stopped a number of universities and colleges from adopting the book as an undergraduate and postgraduate text: a teaching pack for this edition is available from Morgan Kaufmann... to understand the basic rules for representing and organizing it Similarly, these early chapters can be used as the basis of an undergraduate course in data modeling or to support a broader course in database design In fact, we have found that there is sufficient material in Part I to support a postgraduate course in data modeling, particularly if the aim is for the students to develop some facility... Interface 479 History 480 Summarization 480 484 An Initial Model 484 Understanding Existing Data 485 Determining Requirements 485 Determining Sources and Dealing with Differences 485 Shaping Data for Data Marts 487 480 Contents ■ xxi 16.6 Modeling for the Data Mart 16.6.1 16.6.2 16.6.3 488 The Basic Challenge 488 Multidimensional Databases, Stars and Snowflakes 488 Modeling Time-Dependent Data 494 . in Data Modeling? 23 1.11 Is Data Modeling Still Relevant? 24 1.11.1 Costs and Benefits of Data Modeling 25 1.11.2 Data Modeling and Packaged Software 26 1.11.3 Data Integration 27 1.11.4 Data. instances in which Morgan Kaufmann Publishers is aware of a claim, the product names appear in initial capital or all capital letters. Readers, however, should contact the appropriate companies. 20 1.9.1 Process-Driven Approaches 20 1.9.2 Data- Driven Approaches 20 1.9.3 Parallel (Blended) Approaches 22 1.9.4 Object-Oriented Approaches 22 1.9.5 Prototyping Approaches 23 1.9.6 Agile Methods 23 1.10