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Since then, he has been continuously employed in a wide variety of information technology positions, including programmer, programmer/analyst, systems architect, project manager, senior

A Beginner’s Guide

About the Author

Andrew J (Andy) Oppel is a proud graduate of The Boys’ Latin School of Maryland and of

Transylvania University (Lexington, Kentucky) where he earned a BA in computer science

in 1974 Since then, he has been continuously employed in a wide variety of information technology positions, including programmer, programmer/analyst, systems architect, project manager, senior database administrator, database group manager, consultant, database designer, data modeler, and data architect In addition, he has served as a part-time instructor with the University of California, Berkeley, Extension for more than 20 years and received the Honored Instructor Award for the year 2000 His teaching work included developing three courses for UC Extension, “Concepts of Database Management Systems,” “Introduction to Relational Database Management Systems,” and “Data Modeling and Database Design.” He

also earned his Oracle 9i Database Associate certification in 2003 He is currently employed

as a senior data modeler for Blue Shield of California In addition to computer systems, Andy enjoys music (guitar and vocals), amateur radio (Pacific Division Vice Director, American Radio Relay League), and soccer (Referee Instructor, U.S Soccer)

Andy has designed and implemented hundreds of databases for a wide range of applications, including medical research, banking, insurance, apparel manufacturing, telecommunications, wireless communications, and human resources He is the author

of Databases Demystified (McGraw-Hill Professional, 2004) and SQL Demystified (McGraw-Hill Professional, 2005), and is co-author of SQL: A Beginner’s Guide

(McGraw-Hill Professional, 2009) His database product experience includes IMS, DB2, Sybase ASE, Microsoft SQL Server, Microsoft Access, MySQL, and Oracle (versions 7,

8, 8i, 9i, and 10g).

If you have any comments, please contact Andy at andy@andyoppel.com

About the Technical Editor

Todd Meister has been developing using Microsoft technologies for more than ten years

He’s been a Technical Editor on more than 50 books with topics ranging from SQL Server

to the NET Framework In addition to technical editing, he serves as an Assistant Director for Computing Services at Ball State University in Muncie, Indiana He lives in central Indiana with his wife, Kimberly, and their four incredible children Contact Todd at tmeister@sycamoresolutions.com

A Beginner’s Guide

Andrew J Oppel

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Copyright © 2009 by The McGraw-Hill Companies All rights reserved Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in

a database or retrieval system, without the prior written permission of the publisher.

ISBN: 978-0-07-160847-3

MHID: 0-07-160847-8

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Contents

ACKNOWLEDGMENTS xi

INTRODUCTION xiii

PART I Database Concepts 1 Database Fundamentals 3

Properties of a Database 4

The Database Management System 5

Layers of Data Abstraction 6

Physical Data Independence 8

Logical Data Independence 10

Prevalent Database Models 10

Flat Files 10

The Hierarchical Model 13

The Network Model 15

The Relational Model 17

The Object-Oriented Model 19

The Object-Relational Model 21

A Brief History of Databases 22

Why Focus on Relational? 24

2 Exploring Relational Database Components 29

Conceptual Database Design Components 30

Entities 30

vi Databases: A Beginner’s Guide

Attributes 32

Relationships 32

Business Rules 38

Try This 2-1: Exploring the Northwind Database 38

Logical/Physical Database Design Components 42

Tables 42

Columns and Data Types 44

Constraints 46

Integrity Constraints 53

Views 56

3 Forms-based Database Queries 63

QBE: The Roots of Forms-based Queries 64

Getting Started in Microsoft Access 65

The Microsoft Access Relationships Panel 73

The Microsoft Access Table Design View 75

Creating Queries in Microsoft Access 77

Try This 3-1: List All Customers 81

Try This 3-2: Choose Columns to Display 82

Try This 3-3: Sorting Results 84

Try This 3-4: Advanced Sorting 85

Try This 3-5: Choosing Rows to Display 88

Try This 3-6: Compound Row Selection 90

Try This 3-7: Using Not Equal 91

Try This 3-8: Joining Tables 94

Try This 3-9: Limiting Join Results 97

Try This 3-10: Outer Joins 98

Try This 3-11: Microsoft Access SQL 101

Try This 3-12: Multiple Joins and Calculated Columns 103

Try This 3-13: Aggregate Functions 106

Try This 3-14: Self-Joins 109

4 Introduction to SQL 117

A Brief History of SQL 120

Getting Started with Oracle SQL 121

Try This 4-1: Unlock the HR Account and Log in as HR 122

Where’s the Data? 127

Finding Database Objects Using Catalog Views 127

Try This 4-2 Using the Application Express Object Browser 130

Viewing Database Objects Using the Object Browser 130

Data Query Language (DQL): The SELECT Statement 131

Listing All Rows and Columns 132

Limiting Columns to Display 133

Sorting Results 134

Choosing Rows to Display 136

Joining Tables 143

Aggregate Functions 150

Data Manipulation Language (DML) 154

Transaction Support (COMMIT and ROLLBACK) 154

The INSERT Statement 155

The UPDATE Statement 157

The DELETE Statement 158

Data Definition Language (DDL) Statements 159

The CREATE TABLE Statement 160

The ALTER TABLE Statement 161

The CREATE VIEW Statement 162

The CREATE INDEX Statement 163

The DROP Statement 163

Data Control Language (DCL) Statements 164

The GRANT Statement 164

The REVOKE Statement 165

PART II Database Development 5 The Database Life Cycle 171

The Traditional Life Cycle 172

Planning 174

Requirements Gathering 175

Conceptual Design 178

Logical Design 178

Physical Design 179

Construction 179

Implementation and Rollout 180

Ongoing Support 181

Nontraditional Life Cycles 182

Prototyping 182

Rapid Application Development 183

The Project Triangle 183

Try This 5-1: Project Database Management Tasks 184

6 Database Design Using Normalization 189

The Need for Normalization 192

Insert Anomaly 192

Delete Anomaly 193

Update Anomaly 193

Applying the Normalization Process 193

Choosing a Primary Key 196

First Normal Form: Eliminating Repeating Data 198

Second Normal Form: Eliminating Partial Dependencies 200

Third Normal Form: Eliminating Transitive Dependencies 203

Beyond Third Normal Form 205

Contents vii

viii Databases: A Beginner’s Guide

Denormalization 209

Try This 6-1: UTLA Academic Tracking 210

Practice Problems 210

Try This 6-2: Computer Books Company 214

7 Data and Process Modeling 221

Entity Relationship Modeling 222

ERD Formats 222

Super Types and Subtypes 230

Guidelines for Drawing ERDs 235

Process Models 236

The Flowchart 236

The Function Hierarchy Diagram 239

The Swim Lane Diagram 240

The Data Flow Diagram 240

Relating Entities and Processes 245

Try This 7-1: Draw an ERD in Information Engineering (IE) Format 246

8 Physical Database Design 253

Designing Tables 254

Implementing Super Types and Subtypes 259

Naming Conventions 262

Integrating Business Rules and Data Integrity 265

NOT NULL Constraints 267

Primary Key Constraints 267

Referential (Foreign Key) Constraints 268

Unique Constraints 269

Check Constraints 270

Data Types, Precision, and Scale 270

Triggers 270

Designing Views 271

Adding Indexes for Performance 272

Try This 8-1: Mapping a Logical Model to a Physical Database Design 274

PART III Database Implementation 9 Connecting Databases to the Outside World 281

Deployment Models 282

Centralized Model 282

Distributed Model 284

Client/Server Model 285

Connecting Databases to the Web 290

Introduction to the Internet and the Web 290

Components of the Web “Technology Stack” 293

Invoking Transactions from Web Pages 293

Connecting Databases to Applications 295

Connecting Databases via ODBC 295

Connecting Databases via OLE DB 296

Connecting Databases to Java Applications 296

Try This 9-1: Exploring the World Wide Web 297

10 Database Security 303

Why Is Security Necessary? 304

Database Server Security 305

Physical Security 305

Network Security 306

System-Level Security 310

Database Client and Application Security 311

Login Credentials 311

Data Encryption 312

Other Client Considerations 313

Database Access Security 314

Database Security Architectures 315

Schema Owner Accounts 319

System Privileges 320

Object Privileges 320

Roles 321

Views 321

Security Monitoring and Auditing 322

Try This 10-1: Database Object Privileges 323

11 Deploying Databases 329

Cursor Processing 330

Transaction Management 332

What Is a Transaction? 332

DBMS Support for Transactions 333

Try This 11-1: SQL Transaction Support 335

Locking and Transaction Deadlock 337

Performance Tuning 342

Tuning Database Queries 342

Tuning DML Statements 345

Change Control 346

12 Databases for Online Analytical Processing 353

Data Warehouses 355

OLTP Systems Compared with Data Warehouse Systems 356

Data Warehouse Architecture 356

Data Marts 363

Data Mining 364

Try This 12-1: Design Star Schema Fact and Dimension Tables 365

Contents ix

x Databases: A Beginner’s Guide

13 Integrating XML Documents and Objects into Databases 371

Learn the Basics of XML 372

Learn About SQL/XML 376

The XML Data Type 376

SQL/XML Functions 378

SQL/XML Mapping Rule 380

Try This 13-1: Using SQL/XML Functions 383

Object-Oriented Applications 385

Object-Oriented Programming 386

Object-Oriented Languages 386

Object Persistence 387

Object-Relational Databases 392

PART IV Appendices A Answers to Self Tests 401

Chapter 1: Database Fundamentals 402

Chapter 2: Exploring Relational Database Components 404

Chapter 3: Forms-based Database Queries 407

Chapter 4: Introduction to SQL 410

Chapter 5: The Database Life Cycle 413

Chapter 6: Database Design Using Normalization 416

Chapter 7: Data and Process Modeling 419

Chapter 8: Physical Database Design 423

Chapter 9: Connecting Databases to the Outside World 426

Chapter 10: Database Security 430

Chapter 11: Deploying Databases 433

Chapter 12: Databases for Online Analytical Processing 438

Chapter 13: Integrating XML Documents and Objects into Databases 441

B Solutions to the Try This Exercises 447

Try This 5-1 Solution: Project Database Management Tasks 448

Try This 6-1 Solution: UTLA Academic Tracking 449

Try This 6-2 Solution: Computer Books Company 452

Try This 7-1 Solution: Draw an ERD in Information Engineering (IE) Format 454

Try This 8-1 Solution: Mapping a Logical Model to a Physical Database Design 455

Try This 10-1 Solution: Database Object Privileges 455

Try This 11-1 Solution: SQL Transaction Support 456

Try This 12-1 Solution: Design Star Schema Fact and Dimension Tables 456

Try This 13-1 Solution: Using SQL/XML Functions 457

Index 459

Acknowledgments

Many people were involved in the development of Databases: A Beginner’s Guide—

many of whom I do not know by name First, the editors and staff at McGraw-Hill provided untold hours of support for this project I wish to especially thank Editorial Director Wendy Rinaldi as the individual who has provided the most advice and inspiration throughout the development of all my books In fact, it was Wendy who got me started as a McGraw-Hill author I also wish to thank Lisa Theobald for her excellent copy editing and all the other editors, proofreaders, indexers, designers, illustrators, and other participants

My special thanks go to Todd Meister, the technical editor, for his attention to detail and his helpful inputs throughout the editing process Finally, my thanks to my family for their support and understanding as I fit the writing schedule into an already overly busy life

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Introduction

Thirty-five years ago, databases were found only in special research laboratories,

where computer scientists struggled with ways to make them efficient and useful, publishing their findings in countless research papers Today databases are a ubiquitous part of the information technology (IT) industry and business in general We directly and indirectly use databases every day—banking transactions, travel reservations, employment relationships, website searches, online and offline purchases, and most other transactions are recorded in and served by databases

As is the case with many fast-growing technologies, industry standards have lagged behind in the development of database technology, resulting in myriad commercial products, each following a particular software vendor’s vision Moreover, a number

of different database models have emerged, with the relational model being the most

prevalent Databases: A Beginner’s Guide examines all of the major database models,

including hierarchical, network, relational, object-oriented, and object-relational This book concentrates heavily on the relational and object-relational models, however,

because these are the mainstream of the IT industry and will likely remain so in the foreseeable future

The most significant challenge in implementing a database is correctly designing the structure of the database Without a thorough understanding of the problem the database is intended to solve, and without knowledge of the best practices for organizing the required data, the implemented database becomes an unwieldy beast that requires constant attention

xiv Databases: A Beginner’s Guide

Databases: A Beginner’s Guide focuses on the transformation of requirements into a

working data model with special emphasis on a process called normalization, which

has proven to be an effective technique for designing relational databases In fact, normalization can be applied successfully to other database models And, in keeping with the notion that you cannot design an automobile if you have never driven one, the Structured Query Language (SQL) is introduced so that the reader may “drive” a database before delving into the details of designing one

I’ve drawn on my extensive experience as a database designer, administrator, and instructor to provide you with this self-help guide to the fascinating and complex world

of database technology Examples are included using both Microsoft Access and Oracle Publicly available sample databases supplied by these vendors (the Microsoft Access Northwind database and the Oracle Human Resources database schema) are used in example figures whenever possible so that you can try the examples directly on your own computer system A self test is provided at the end of each chapter to help reinforce your learning

Who Should Read This Book

Databases: A Beginner’s Guide is recommended for anyone trying to build a foundation

in database design and management, whether for personal or professional use The book

is designed specifically for those who are new or relatively new to database technology; however, those of you who need a refresher in normalization and database design and management will also find this book beneficial Whether you’re an experienced developer, you’ve had some development experience, you’re a database administrator, or

you’re new to programming and databases, Databases: A Beginner’s Guide provides a

strong foundation that will be useful to any of you wanting to learn more about database technology In fact, any of the following individuals will find this book helpful when trying to understand and use databases:

● The novice new to database design and SQL programming

● The analyst or manager who wants a better understanding of how to design,

implement, and access databases

● The database administrator who wants to learn more about database design

● The technical support professional or testing/QA engineer who must perform ad hoc queries against SQL databases

● The web developer writing applications that require databases for data persistence