Data Warehousing Fundamentals A Comprehensive Guide for IT Professionals phần 1 ppt

251 1 Top-Down Versus Bottom-Up Approach 26 1 A Practical Approach 27 1 Overview of the Components 28 1 Source Data Component 28 1 Data Staging Component 31 1 Data Storage Component 33 1

Trang 1

DATA WAREHOUSING

FUNDAMENTALS

Data Warehousing Fundamentals: A Comprehensive Guide for IT Professionals Paulraj Ponniah

Trang 2

DATA WAREHOUSING FUNDAMENTALS

A Comprehensive Guide for

IT Professionals

PAULRAJ PONNIAH

A Wiley-Interscience Publication

JOHN WILEY & SONS, INC.

New York / Chichester / Weinheim / Brisbane / Singapore / Toronto

Trang 3

Designations used by companies to distinguish their products are often claimed as trademarks In all instances where John Wiley & Sons, Inc., is aware of a claim, the product names appear in initial capital or ALL CAPITAL LETTERS Readers, however, should contact the appropriate companies for more complete information regarding trademarks and registration.

No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic

or mechanical, including uploading, downloading, printing, decompiling, recording or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without the prior written permission of the Publisher Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 605 Third Avenue, New York, NY 10158-0012, (212) 850-6011, fax (212) 850-6008, E-Mail: PERMREQ @ WILEY.COM.

This publication is designed to provide accurate and authoritative information in regard to the subject matter covered It is sold with the understanding that the publisher is not engaged in

rendering professional services If professional advice or other expert assistance is required, theservices of a competent professional person should be sought

ISBN 0-471-22162-7

This title is also available in print as ISBN 0-471-41254-6

For more information about Wiley products, visit our web site at www.Wiley.com

Trang 5

Part 1 OVERVIEW AND CONCEPTS

1 Chapter Objectives 1

1 Escalating Need for Strategic Information 2

1 The Information Crisis 3

1 Technology Trends 4

1 Opportunities and Risks 5

1 Failures of Past Decision-Support Systems 7

1 History of Decision-Support Systems 8

1 Inability to Provide Information 9

1 Operational Versus Decision-Support Systems 9

1 Making the Wheels of Business Turn 10

1 Watching the Wheels of Business Turn 10

1 Different Scope, Different Purposes 10

1 Data Warehousing—The Only Viable Solution 12

1 A New Type of System Environment 12

1 Processing Requirements in the New Environment 12

1 Business Intelligence at the Data Warehouse 12

1 Data Warehouse Defined 13

1 A Simple Concept for Information Delivery 14

vii

Trang 6

1 An Environment, Not a Product 14

1 A Blend of Many Technologies 14

1 Data Warehouses and Data Marts 24

1 How are They Different? 251

1 Top-Down Versus Bottom-Up Approach 26

1 A Practical Approach 27

1 Overview of the Components 28

1 Source Data Component 28

1 Data Staging Component 31

1 Data Storage Component 33

1 Information Delivery Component 34

1 Metadata Component 35

1 Management and Control Component 35

1 Metadata in the Data Warehouse 35

1 Continued Growth in Data Warehousing 40

1 Data Warehousing is Becoming Mainstream 40

1 Data Warehouse Expansion 41

1 Vendor Solutions and Products 42

Trang 7

1 Data Warehousing and ERP 52

1 Data Warehousing and KM 53

1 Data Warehousing and CRM 54

1 Active Data Warehousing 56

1 Emergence of Standards 56

1 Metadata 57

1 Web-Enabled Data Warehouse 58

1 The Warehouse to the Web 59

1 The Web to the Warehouse 59

1 The Web-Enabled Configuration 60

1 Review Questions 61

1 Exercises 62

Part 2 PLANNING AND REQUIREMENTS

1 Chapter Objectives 63

1 Planning Your Data Warehouse 64

1 Key Issues 64

1 Business Requirements, Not Technology 66

1 Top Management Support 67

1 Justifying Your Data Warehouse 67

1 The Overall Plan 68

1 The Data Warehouse Project 69

1 How is it Different? 70

1 Assessment of Readiness 71

1 The Life-Cycle Approach 71

1 The Development Phases 73

1 The Project Team 74

1 Organizing the Project Team 75

1 Roles and Responsibilities 75

1 Skills and Experience Levels 77

1 User Participation 78

1 Project Management Considerations 80

1 Guiding Principles 81

CONTENTS ix

Trang 8

1 Warning Signs 82

1 Success Factors 82

1 Anatomy of a Successful Project 83

1 Adopt a Practical Approach 84

1 Usage of Information Unpredictable 90

1 Dimensional Nature of Business Data 90

1 Examples of Business Dimensions 92

1 Information Packages—A New Concept 93

1 Requirements Not Fully Determinate 93

1 Business Dimensions 95

1 Dimension Hierarchies/Categories 95

1 Key Business Metrics or Facts 96

1 Requirements Gathering Methods 97

1 Interview Techniques 99

1 Adapting the JAD Methodology 102

1 Review of Existing Documentation 103

1 Requirements Definition: Scope and Content 104

1 Data Sources 105

1 Data Transformation 105

1 Data Storage 105

1 Information Delivery 105

1 Information Package Diagrams 106

1 Requirements Definition Document Outline 106

1 Structure for Business Dimensions 112

1 Structure for Key Measurements 112

1 Levels of Detail 113

1 The Architectural Plan 113

1 Composition of the Components 114

x CONTENTS

Trang 9

1 Special Considerations 115

1 Tools and Products 118

1 Data Storage Specifications 119

1 DBMS Selection 120

1 Storage Sizing 120

1 Information Delivery Strategy 121

1 Queries and Reports 122

1 Types of Analysis 123

1 Information Distribution 1231

1 Decision Support Applications 123

1 Growth and Expansion 123

1 Chapter Summary 124

1 Review Questions 124

1 Exercises 125

Part 3 ARCHITECTURE AND INFRASTRUCTURE

1 Complex Analysis and Quick Response 131

1 Flexible and Dynamic 131

1 Metadata-driven 132

1 Architectural Framework 132

1 Architecture Supporting Flow of Data 132

1 The Management and Control Module 133

Trang 10

1 Queries and Reports 170

1 Online Analytical Processing (OLAP) 170

1 Alert Systems 170

1 Middleware and Connectivity 170

1 Data Warehouse Management 170

1 Why Metadata is Important 173

1 A Critical Need in the Data Warehouse 175

1 Why Metadata is Vital for End-Users 177

1 Why Metadata is Essential for IT 179

1 Automation of Warehousing Tasks 181

1 Establishing the Context of Information 183

1 Metadata Types by Functional Areas 183

Trang 11

Part 4 DATA DESIGN AND DATA PREPARATION

1 1Chapter Objectives 203

1 1From Requirements to Data Design 203

1 2 Design Decisions 204

1 2 Dimensional Modeling Basics 204

1 2 E-R Modeling Versus Dimensional Modeling 209

1 2 Use of CASE Tools 209

1 1The STAR Schema 210

1 2 Review of a Simple STAR Schema 210

1 2 Inside a Dimension Table 212

1 2 Inside the Fact Table 214

1 2 The Factless Fact Table 216

1 1Advantages of the STAR Schema 220

1 2 Easy for Users to Understand 220

1 2 Optimizes Navigation 221

1 2 Most Suitable for Query Processing 222

1 2 STARjoin and STARindex 223

1 1Chapter Summary 223

1 1Review Questions 224

1 1Exercises 224

CONTENTS xiii

Trang 12

11 Dimensional Modeling: Advanced Topics 225

1 1Updates to the Dimension Tables 226

1 2 Slowly Changing Dimensions 226

1 2 Type 1 Changes: Correction of Errors 227

1 2 Type 2 Changes: Preservation of History 228

1 2 Type 3 Changes: Tentative Soft Revisions 230

1 1Aggregate Fact Tables 239

1 2 Fact Table Sizes 241

1 2 Need for Aggregates 242

1 2 Aggregating Fact Tables 243

1 2 Aggregation Options 247

1 1Families of STARS 249

1 2 Snapshot and Transaction Tables 250

1 2 Core and Custom Tables 251

1 2 Supporting Enterprise Value Chain or Value Circle 251

1 2 Most Important and Most Challenging 259

1 2 Time-consuming and Arduous 260

1 2 ETL Requirements and Steps 260

1 2 Key Factors 261

1 1Data Extraction 262

1 2 Source Identification 263

1 2 Data Extraction Techniques 263

1 2 Evaluation of the Techniques 270

xiv CONTENTS

Trang 13

1 1Data Transformation 271

1 2 Data Transformation: Basic Tasks 272

1 2 Major Transformation Types 273

1 2 Data Integration and Consolidation 275

1 2 Transformation for Dimension Attributes 277

1 2 How to Implement Transformation 277

1 1Data Loading 279

1 2 Applying Data: Techniques and Processes 280

1 2 Data Refresh Versus Update 282

1 2 Procedure for Dimension Tables 283

1 2 Fact Tables: History and Incremental Loads 284

1 2 ETL Tool Options 285

1 2 Reemphasizing ETL Metadata 286

1 2 ETL Summary and Approach 287

1 1Why is Data Quality Critical? 292

1 2 What is Data Quality? 292

1 2 Benefits of Improved Data Quality 295

1 2 Types of Data Quality Problems 296

1 1Data Quality Challenges 299

1 2 Sources of Data Pollution 299

1 2 Validation of Names and Addresses 301

1 2 Costs of Poor Data Quality 302

1 1Data Quality Tools 303

1 2 Categories of Data Cleansing Tools 303

1 2 Error Discovery Features 303

1 2 Data Correction Features 303

1 2 The DBMS for Quality Control 304

1 1Data Quality Initiative 304

1 2 Data Cleansing Decisions 305

1 2 Who Should be Responsible? 307

1 2 The Purification Process 309

1 2 Practical Tips on Data Quality 311

CONTENTS xv

Trang 14

Part 5 INFORMATION ACCESS AND DELIVERY

1 1Information from the Data Warehouse 316

1 2 Data Warehouse Versus Operational Systems 316

1 2 What They Need 326

1 2 How to Provide Information 329

1 1Information Delivery Tools 335

1 2 The Desktop Environment 335

1 2 Methodology for Tool Selection 335

1 2 Tool Selection Criteria 338

1 2 Information Delivery Framework 340

1 1Demand for Online Analytical Processing 344

1 2 Need for Multidimensional Analysis 344

1 2 Fast Access and Powerful Calculations 345

1 2 Limitations of Other Analysis Methods 347

1 2 OLAP is the Answer 349

1 2 OLAP Definitions and Rules 349

1 2 OLAP Characteristics 352

1 1Major Features and Functions 353

1 2 General Features 353

1 2 Dimensional Analysis 353

1 2 What are Hypercubes? 357

1 2 Drill-Down and Roll-Up 360

1 2 Slice-and-Dice or Rotation 362

xvi CONTENTS

Trang 15

1 2 Uses and Benefits 363

1 2 Overview of Variations 364

1 2 The MOLAP Model 365

1 2 The ROLAP Model 366

1 2 ROLAP Versus MOLAP 367

1 1OLAP Implementation Considerations 368

1 2 Data Design and Preparation 368

1 2 Administration and Performance 370

1 1Web-Enabled Data Warehouse 378

1 2 Why the Web? 378

1 2 Convergence of Technologies 380

1 2 Adapting the Data Warehouse for the Web 381

1 2 The Web as a Data Source 382

1 1Web-Based Information Delivery 383

1 2 Expanded Usage 383

1 2 New Information Strategies 385

1 2 Browser Technology for the Data Warehouse 387

1 2 Security Issues 389

1 1OLAP and the Web 389

1 2 Enterprise OLAP 389

1 2 Web-OLAP Approaches 390

1 2 OLAP Engine Design 390

1 1Building a Web-Enabled Data Warehouse 391

1 2 Nature of the Data Webhouse 391

1 2 Implementation Considerations 393

1 2 Putting the Pieces Together 394

1 2 Web Processing Model 394

CONTENTS xvii

Trang 16

17 Data Mining Basics 399

1 1What is Data Mining? 400

1 2 Data Mining Defined 401

1 2 The Knowledge Discovery Process 402

1 2 OLAP Versus Data Mining 404

1 2 Data Mining and the Data Warehouse 406

1 1Major Data Mining Techniques 408

1 2 Moving into Data Mining 419

1 1Data Mining Applications 422

1 2 Benefits of Data Mining 423

1 2 Applications in Retail Industry 424

1 2 Applications in Telecommunications Industry 425

1 2 Applications in Banking and Finance 426

Part 6 IMPLEMENTATION AND MAINTENANCE

1 1Physical Design Steps 430

1 2 Develop Standards 430

1 2 Create Aggregates Plan 431

1 2 Determine the Data Partitioning Scheme 431

1 2 Establish Clustering Options 432

1 2 Prepare an Indexing Strategy 432

1 2 Assign Storage Structures 432

1 2 Complete Physical Model 433

1 1Physical Design Considerations 433

1 2 Physical Design Objectives 433

1 2 From Logical Model to Physical Model 434

1 2 Physical Model Components 435

1 2 Significance of Standards 436

1 1Physical Storage 438

xviii CONTENTS

Trang 17

1 2 Storage Area Data Structures 439

1 2 Optimizing Storage 440

1 2 Using RAID Technology 442

1 2 Estimating Storage Sizes 442

1 1Indexing the Data Warehouse 443

1 2 Indexing Overview 443

1 2 B-Tree Index 445

1 2 Bitmapped Index 446

1 2 Clustered Indexes 448

1 2 Indexing the Fact Table 448

1 2 Indexing the Dimension Tables 449

1 1Performance Enhancement Techniques 449

1 1Major Deployment Activities 456

1 2 Complete User Acceptance 456

1 2 Perform Initial Loads 457

1 2 Get User Desktops Ready 458

1 2 Complete Initial User Training 459

1 2 Institute Initial User Support 460

1 2 Deploy in Stages 460

1 1Considerations for a Pilot 462

1 2 When Is a Pilot Data Mart Useful? 462

1 2 Types of Pilot Projects 463

1 2 Choosing the Pilot 465

1 2 Expanding and Integrating the Pilot 466

Trang 18

1 1Backup and Recovery 470

1 2 Why Back Up the Data Warehouse? 470

1 2 Using Statistics for Growth Planning 480

1 2 Using Statistics for Fine-Tuning 480

1 2 Publishing Trends for Users 481

1 1User Training and Support 481

1 2 User Training Content 482

1 2 Preparing the Training Program 482

1 2 Delivering the Training Program 484

1 2 Data Model Revisions 489

1 2 Information Delivery Enhancements 489

1 2 Ongoing Fine-Tuning 490

Appendix A Project Life Cycle Steps and Checklists 493

Appendix C Guidelines for Evaluating Vendor Solutions 499

xx CONTENTS

Trang 19

I am delighted to share my thoughts with information technology professionals about my

faculty colleague Paulraj Ponniah’s textbook Data Warehousing Fundamentals In the

spring of 1998, Raritan Valley Community College decided to offer a course on datawarehousing This was mainly through the initiative of Dr Ponniah, who had been teach-ing our database design and development course for several years It was very difficult tofind a good textbook for a college course on data warehousing We had to settle for a bookthat was not quite suitable In order to make the course effective, Paul had to supplementthe book with his own data warehousing seminar materials Our students, primarily ITprofessionals from local industries, received the course very well Now this magnificenttextbook on data warehousing comes to you through the foresight and diligent work of Dr.Ponniah, along with the insightful support of the publishers, John Wiley and Sons This book has numerous features that make it a winner:

앫 The order of topics is very logical

앫 The choice of topics is quite appropriate for a comprehensive introductory book.The coverage of topics is also very well balanced

앫 The subject matter is logically structured, with chapters covering essential nents of the data warehousing field The sequence of topics is well planned to pro-vide a seamless transition from design to implementation

compo-앫 Within each chapter, the continuity of topics is excellent

앫 None of the topics included in the textbook is superfluous to the basic objectives

앫 The material included is technically correct and up-to-date The figures

appropriate-ly enhance and amplify the topics

앫 Ample review questions and exercises can be found at the end of each chapter This

is something lacking in most books on data warehousing These review questionsand exercises are pedagogically sound They are designed to test the knowledge, notthe ignorance, of the reader

xxi

Trang 20

Dr Ponniah’s writing style is clear and concise Because of the simplicity and pleteness of this book, I believe it will find a definite market niche, particularly amongcollege students, not-so-technically savvy IT people, and data warehousing mavens.

com-In spite of a plethora of books on data warehousing by luminaries such as Kimball, com-mon, Barquin, and Singh, this book fulfills a special purpose, and information technologyprofessionals will definitely benefit from reading it In addition, the book should be wellreceived by college professors for use by students in their data warehousing courses Toput it succinctly, this book fills a void in the midst of plenty

In-In summary, Dr Ponniah has produced a winner for both students and experienced ITprofessionals As someone who has been in IT education for many years, I certainly rec-ommend this book to college professors and seminar leaders for their data warehousingcourses

PRATAPP REDDY, Ph.D

Professor and Chair of CIS DepartmentRaritan Valley Community CollegeNorth Branch, New Jersey

xxii FOREWORD

Trang 21

THIS BOOK IS FOR YOU

Are you an information technology professional watching, with great interest, the massiveunfolding of the data warehouse movement? Are you contemplating a move into this newarea of opportunity? Are you a systems analyst, programmer, data analyst, database ad-ministrator, project leader, or software engineer eager to grasp the fundamentals of datawarehousing? Do you wonder how many different books you may have to read to learn thebasics? Are you lost in the maze of the literature and products on the subject? Do youwish for a single publication on data warehousing, clearly and specifically designed for ITprofessionals? Do you need a textbook that helps you learn the fundamentals in sufficientdepth—not more, not less? If you answered “yes” to any of the above, this book is writtenspecially for you

This is the one definitive book on data warehousing clearly intended for IT

profession-als The organization and presentation of the book are specially tuned for IT professionprofession-als.This book does not presume to target anyone and everyone remotely interested in the sub-ject for some reason or another, but is written to address the specific needs of IT profes-sionals like you It does not tend to emphasize certain aspects and neglect other criticalones The book takes you over the entire landscape of data warehousing

How can this book be exactly suitable for IT professionals? As a veteran IT

profession-al with wide and intensive industry experience, as a successful database and data housing consultant for many years, and as one who teaches data warehousing fundamen-tals in the college classroom and in public seminars, I have come to appreciate the preciseneeds of IT professionals, and in every chapter I have incorporated these requirements ofthe IT community

ware-xxiii

Trang 22

THE SCENARIO

Why are companies rushing into data warehousing? Why is there a tremendous surge ininterest? Data warehousing is no longer a purely novel idea just for research and experi-mentation It has become a mainstream phenomenon True, the data warehouse is not inevery doctor’s office yet, but neither is it confined to only high-end businesses More thanhalf of all U.S companies and a large percentage of worldwide businesses have made acommitment to data warehousing

In every industry across the board, from retail chain stores to financial institutions,from manufacturing enterprises to government departments, and from airline companies

to utility businesses, data warehousing is revolutionizing the way people perform businessanalysis and make strategic decisions Every company that has a data warehouse is realiz-ing the enormous benefits translated into positive results at the bottom line These compa-nies, now incorporating Web-based technologies, are enhancing the potential for greaterand easier delivery of vital information

Over the past five years, hundreds of vendors have flooded the market with numerousdata warehousing products Vendor solutions and products run the gamut of data ware-housing—data modeling, data acquisition, data quality, data analysis, metadata, and so

on The market is already large and continues to grow

CHANGED ROLE OF IT

In this scenario, information technology departments of all progressive companies ceive a radical change in their roles IT is no longer required to create every report andpresent every screen for providing information to the end-users IT is now charged withthe building of information delivery systems and letting the end-users themselves retrieveinformation in innovative ways for analysis and decision making Data warehousing isproving to be just that type of successful information delivery system

per-IT professionals responsible for building data warehouses need to revise their mindsetsabout building applications They have to understand that a data warehouse is not a one-size-fits-all proposition; they must get a clear understanding of the extraction of data fromsource systems, data transformations, data staging, data warehouse architecture, infra-structure, and the various methods of information delivery

In short, IT professionals, like you, must get a strong grip on the fundamentals of datawarehousing

WHAT THIS BOOK CAN DO FOR YOU

The book is comprehensive and detailed You will be able to study every significant topic

in planning, requirements, architecture, infrastructure, design, data preparation, tion delivery, deployment, and maintenance It is specially designed for IT professionals;you will be able to follow the presentation easily because it is built upon the foundation ofyour background as an IT professional, your knowledge, and the technical terminology fa-miliar to you It is organized logically, beginning with an overview of concepts, moving

informa-on to planning and requirements, then to architecture and infrastructure, informa-on to data design,then to information delivery, and concluding with deployment and maintenance This pro-

xxiv PREFACE

Trang 23

gression is typical of what you are most familiar with in your experience and day-to-daywork.

The book provides an interactive learning experience It is not a one-way lecture Youparticipate through the review questions and exercises at the end of each chapter For eachchapter, the objectives set the theme and the summary provides a list of the topics cov-ered You can relate each concept and technique to the data warehousing industry andmarketplace You will notice a substantial number of industry examples Although intend-

ed as a first course on fundamentals, this book provides sufficient coverage of each topic

so that you can comfortably proceed to the next step of specialization for specific roles in

a data warehouse project

Featuring all the significant topics in appropriate measure, this book is eminently able as a textbook for serious self-study, a college course, or a seminar on the essentials Itprovides an opportunity for you to become a data warehouse expert

suit-I acknowledge my indebtedness to the authors listed in the reference section at the end

of the book Their insights and observations have helped me cover adequately the topics Imust also express my appreciation to my students and professional colleagues Our inter-actions have enabled me to shape this textbook according to the needs of IT professionals

PAULRAJPONNIAH, Ph.D

Edison, New Jersey

June 2001

PREFACE xxv

Trang 24

DATA WAREHOUSING FUNDAMENTALS

Trang 25

CHAPTER 1

THE COMPELLING NEED

FOR DATA WAREHOUSING

CHAPTER OBJECTIVES

앫 Understand the desperate need for strategic information

앫 Recognize the information crisis at every enterprise

앫 Distinguish between operational and informational systems

앫 Learn why all past attempts to provide strategic information failed

앫 Clearly see why data warehousing is the viable solution

As an information technology professional, you have worked on computer applications

as an analyst, programmer, designer, developer, database administrator, or project

manag-er You have been involved in the design, implementation, and maintenance of systemsthat support day-to-day business operations Depending on the industries you haveworked in, you must have been involved in applications such as order processing, generalledger, inventory, in-patient billing, checking accounts, insurance claims, and so on These applications are important systems that run businesses They process orders,maintain inventory, keep the accounting books, service the clients, receive payments, andprocess claims Without these computer systems, no modern business can survive Com-panies started building and using these systems in the 1960s and have become completelydependent on them As an enterprise grows larger, hundreds of computer applications areneeded to support the various business processes These applications are effective in whatthey are designed to do They gather, store, and process all the data needed to successfullyperform the daily operations They provide online information and produce a variety ofreports to monitor and run the business

In the 1990s, as businesses grew more complex, corporations spread globally, andcompetition became fiercer, business executives became desperate for information to staycompetitive and improve the bottom line The operational computer systems did provideinformation to run the day-to-day operations, but what the executives needed were differ-ent kinds of information that could be readily used to make strategic decisions They

1

Data Warehousing Fundamentals: A Comprehensive Guide for IT Professionals Paulraj Ponniah

Trang 26

wanted to know where to build the next warehouse, which product lines to expand, andwhich markets they should strengthen The operational systems, important as they were,could not provide strategic information Businesses, therefore, were compelled to turn tonew ways of getting strategic information.

Data warehousing is a new paradigm specifically intended to provide vital strategic formation In the 1990s, organizations began to achieve competitive advantage by build-ing data warehouse systems Figure 1-1 shows a sample of strategic areas where datawarehousing is already producing results in different industries

in-We will now briefly examine a crucial question: why do enterprises really need datawarehouses? This discussion is important because unless we grasp the significance of thiscritical need, our study of data warehousing will lack motivation So, please pay close at-tention

ESCALATING NEED FOR STRATEGIC INFORMATION

While we discuss the clamor by enterprises for strategic information, we need to look atthe prevailing information crisis that is holding them back as well as the technology trends

of the past few years that are working in our favor, enabling us to provide strategic mation Our discussion of the need for strategic information will not be complete unless

infor-we study the opportunities provided by strategic information and the risks facing a pany without such information

com-Who needs strategic information in an enterprise? What exactly do we mean by gic information? The executives and managers who are responsible for keeping the enter-prise competitive need information to make proper decisions They need information toformulate the business strategies, establish goals, set objectives, and monitor results Here are some examples of business objectives:

strate-앫 Retain the present customer base

앫 Increase the customer base by 15% over the next 5 years

2 THE COMPELLING NEED FOR DATA WAREHOUSING

Organizations achieve competitive advantage:

Figure 1-1 Organizations’ use of data warehousing

Định dạng
Số trang	53
Dung lượng	416,67 KB