Apress - Pro SQL Server 2008 Relational Database Design and Implementation (2008)01

this print for content only—size & color not accurate spine = 1.2793" 680 page countPro SQL Server 2008 Relational Database Design and Implementation Dear Reader, I have written this boo

this print for content only—size & color not accurate spine = 1.2793" 680 page count

Pro SQL Server 2008 Relational Database Design and Implementation

Dear Reader,

I have written this book for you, the database professional, to give you the knowledge and practical steps needed to design and implement database solutions using SQL Server I have filled this book with hard-won knowledge and experience that I’ve accumulated through many years of working with relational databases—including nearly every version of SQL Server

My first goal in writing this book is to explain many of the important concepts you need to learn from a database design textbook Secondly, I will show practi-cal techniques for applying these concepts to build solid SQL Server database solutions

I start with the concepts of relational theory, data modeling, and normaliza-tion Then I show you how to produce a database that works right the first time, using common design patterns and all of the objects types that SQL Server gives you From there, I give you practical advice on implementing your systems with concurrency and performance in mind

Throughout this book, you will find that I emphasize the practical while always giving proper respect to the underlying theory Great practices always rest on a solid theoretical foundation After reading this book, you will have the tools you need to get going with your database implementation And if we have

a bit of fun along the way, that’ll be our secret

Thank you, Louis Davidson

Author of

Pro SQL Server 2005

Database Design and

Optimization

Pro SQL Server 2000

Database Design

US $59.99

Shelve in

Databases/SQL Server

User level:

Intermediate–Advanced

Pro

SQL Server 2008

Relational Database

Louis Davidson

With Kevin Kline, Scott Klein, and Kurt Windisch

Foreword by Paul Nielsen, SQL Server MVP

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Design for performance! Create optimized SQL Server databases that scale well and are logically sound in order to meet your business requirements.

ISBN 978-1-4302-0866-2

9 781430 208662

5 5 9 9 9

Louis Davidson

With Kevin Kline, Scott Klein,

and Kurt Windisch

Pro SQL Server 2008 Relational Database Design and

Implementation

Pro SQL Server 2008 Relational Database Design and Implementation

Copyright © 2008 by Louis Davidson

All rights reserved No part of this work may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage or retrieval system, without the prior written permission of the copyright owner and the publisher

ISBN-13 (pbk): 978-1-4302-0866-2

ISBN-13 (electronic): 978-1-4302-0867-9

Printed and bound in the United States of America 9 8 7 6 5 4 3 2 1

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The source code for this book is available to readers at http://www.apress.com

To my father-in-law, Verlin Wheeler He passed away during the writing of this book, and I really never got to know him as I was told he was in his younger days At the very least, he rivaled my love for gadgets and was an early adopter of lots of technology, like satellite dishes and even computers I use his computer every day to manage my media collection—

he probably would have liked that, though I think he would have preferred to have used

the media in the library.

Contents at a Glance

Foreword xv

About the Author xvii

About the Technical Reviewers xix

Acknowledgments xxi

Introduction xxiii

■ CHAPTER 1 Introduction to Database Concepts 1

■ CHAPTER 2 The Language of Data Modeling 33

■ CHAPTER 3 Conceptual Data Modeling 71

■ CHAPTER 4 The Normalization Process 117

■ CHAPTER 5 Implementing the Base Table Structures 177

■ CHAPTER 6 Protecting the Integrity of Your Data 273

■ CHAPTER 7 Patterns and Query Techniques 339

■ CHAPTER 8 Securing Access to the Data 385

■ CHAPTER 9 Table Structures and Indexing 447

■ CHAPTER 10 Coding for Concurrency 499

■ CHAPTER 11 Considering Data Access Strategies 555

■ APPENDIX A Codd’s 12 Rules for an RDBMS 595

■ APPENDIX B Scalar Datatype Reference 603

■ INDEX 635

v

Foreword xv

About the Author xvii

About the Technical Reviewers xix

Acknowledgments xxi

Introduction xxiii

■ CHAPTER 1 Introduction to Database Concepts 1

Database Design Phases 2

Conceptual 3

Logical 5

Implementation 6

Physical 7

Relational Data Structures 7

Database and Schema 8

Tables, Rows, and Columns 8

The Information Principle 12

Domains 15

Metadata 16

Keys 16

Missing Values (NULLs) 22

Relationship Between Entities 23

Data Access Language (SQL) 29

Understanding Dependencies 30

Functional Dependency 31

Determinant 31

Summary 32

■ CHAPTER 2 The Language of Data Modeling 33

Introduction to Data Modeling 33

Entities 35

Attributes 38

Primary Keys 39

Alternate Keys 40

vii

Foreign Keys 42

Domains 42

Naming 45

Relationships 46

Identifying Relationships 47

Nonidentifying Relationships 47

Role Names 50

Relationship Cardinality 52

Verb Phrases (Relationship Names) 59

Descriptive Information 61

Alternative Modeling Methodologies 62

Information Engineering 63

Chen ERD 65

Visio 66

Management Studio Database Diagrams 67

Best Practices 68

Summary 69

■ CHAPTER 3 Conceptual Data Modeling 71

Understanding the Requirements 72

Documenting the Process 73

Requirements Gathering 74

Client Interviews 75

Questions to Be Answered 76

Existing Systems and Prototypes 80

Other Types of Documentation 80

Identifying Objects and Processes 82

Identifying Entities 83

Relationships Between Entities 91

Identifying Attributes and Domains 98

Identifying Business Rules and Processes 108

Identifying Business Rules 109

Identifying Fundamental Processes 110

Finishing the Conceptual Model 112

Identifying Obvious Additional Data Needs 113

Review with the Client 114

Repeat Until the Customer Agrees with Your Model 114

Best Practices 115

Summary 115

■ CHAPTER 4 The Normalization Process 117

Why Normalize? 118

Eliminating Duplicated Data 118

Avoiding Unnecessary Coding 119

Keeping Tables Thin 119

Maximizing Clustered Indexes 119

Lowering the Number of Indexes Per Table 119

How Far to Normalize? 120

The Process of Normalization 120

Entity and Attribute Shape: First Normal Form 121

All Attributes Must Be Atomic 121

All Instances in an Entity Must Contain the Same Number of Values 126

All Occurrences of an Entity Type in an Entity Must Be Different 127

Programming Anomalies Avoided by First Normal Form 128

Clues That An Existing Design Is Not in First Normal Form 133

Relationships Between Attributes 134

Second Normal Form 135

Third Normal Form 140

Boyce-Codd Normal Form 147

Multivalued Dependencies in Entities 151

Fourth Normal Form 151

Fifth Normal Form 165

Denormalization 166

Best Practices 167

Summary 167

Bonus Example 168

The Story of the Book So Far 174

■ CHAPTER 5 Implementing the Base Table Structures 177

Reviewing the Logical Design 181

Transforming the Design 181

Choosing Names 182

Dealing with Subtypes 186

Determining Tree Implementation 190

Choosing Key Implementation 191

Determining Domain Implementation 198

Setting Up Schemas 209

Reviewing the “Final” Implementation Model 210

Implementing the Design 211

Creating the Basic Table Structures 212

Adding Uniqueness Constraints 221

Building Default Constraints 228

Adding Relationships (Foreign Keys) 235

Dealing with Collations and Sorting 246

Computed Columns 251

Implementing User-Defined Datatypes 254

Documenting Your Database 263

Working with Dependency Information 266

Best Practices 270

Summary 271

■ CHAPTER 6 Protecting the Integrity of Your Data 273

Best Practices 274

Automatic Data Protection 276

Declarative Data Protection 277

Basic Syntax 279

CHECK Constraints Based on Simple Expressions 281

CHECK Constraints Based on Functions 283

Errors Caused by Constraints 288

DML Triggers 290

Handling Errors from Triggers and Constraints 327

Manual Data Protection 330

Stored Procedures 332

Client Code 334

More Best Practices 337

Summary 338

■ CHAPTER 7 Patterns and Query Techniques 339

Precalculated Values 340

Sequence Tables 341

Calculations with Dates 348

Binary Large Valued Objects (BLOB) 357

Storing User-Specified Data 360

Big Old List of Generic Columns 362

Entity-Attribute-Value (EAV) 363

Adding Columns to a Table 367

Commonly Implemented Objects 373

Anti-patterns 374

One-Size-Fits-All Key Domain 375

Generic Key References 378

Overusing Unstructured Data 381

Summary 383

The Continuing Story of the Book So Far 384

■ CHAPTER 8 Securing Access to the Data 385

Principals and Securables 387

Database Security Overview 388

Impersonation 389

Permissions 391

Controlling Access to Objects 393

Roles 396

Schemas 403

Controlling Object Access Via T-SQL Coded Objects 405

Stored Procedures and Scalar Functions 406

Impersonation Within Objects 408

Crossing Database Lines 413

Different Server (Distributed Queries) 418

Views and Table-Valued Functions 419

General Usage 419

Implementing Configurable Row-Level Security with Views 422

Obfuscating Data 426

Monitoring and Auditing 429

Server and Database Audit 430

Watching Table History Using DML Triggers 434

DDL Triggers 438

Logging with Profiler 441

Best Practices 443

Summary 444

■ CHAPTER 9 Table Structures and Indexing 447

Physical Database Structure 448

Files and Filegroups 448

Extents and Pages 452

Data on Pages 454

Partitioning 458

Indexes Overview 460

Basic Index Structure 460

Index Types 462

Clustered Indexes 463

Nonclustered Indexes 464

Nonclustered Indexes on Clustered Tables 465

Basics of Index Creation 468

Basic Index Usage Patterns 470

Using Clustered Indexes 472

Using Nonclustered Indexes 474

Using Unique Indexes 487

Advanced Index Usage Scenarios 487

Foreign Key Indexes 487

Indexed Views 492

Best Practices 495

Summary 496

■ CHAPTER 10 Coding for Concurrency 499

What Is Concurrency? 500

Query Optimization Basics 501

OS and Hardware Issues 504

Transactions 505

Transaction Syntax 506

Compiled SQL Server Code 514

SQL Server Concurrency Controls 522

Locks 522

Isolation Levels 527

Coding for Integrity and Concurrency 539

Pessimistic Locking 539

Implementing a Single Threaded Code Block 541

Optimistic Locking 544

Row-Based Locking 546

Logical Unit of Work 550

Best Practices 552

Summary 553

■ CHAPTER 11 Considering Data Access Strategies 555

Ad Hoc SQL 557

Advantages 557

Pitfalls 565

Stored Procedures 569

Encapsulation 571

Dynamic Procedures 572

Security 574

Performance 576

Pitfalls 578

Opinions 582

T-SQL and the CLR 584

Guidelines for Choosing T-SQL 588

Guidelines for Choosing NET 589

CLR Object Types 589

Best Practices 592

Summary 594

■ APPENDIX A Codd’s 12 Rules for an RDBMS 595

Rule 1: The Information Rule 595

Rule 2: Guaranteed Access Rule 596

Rule 3: Systematic Treatment of NULL Values 596

Rule 4: Dynamic Online Catalog Based on the Relational Model 596

Rule 5: Comprehensive Data Sublanguage Rule 597

Rule 6: View Updating Rule 597

Rule 7: High-Level Insert, Update, and Delete 598

Rule 8: Physical Data Independence 598

Rule 9: Logical Data Independence 599

Rule 10: Integrity Independence 600

Rule 11: Distribution Independence 600

Rule 12: Non-Subversion Rule 600

Summary 601

■ APPENDIX B Scalar Datatype Reference 603

Precise Numeric Data 605

Integer Values 605

Decimal Values 608

Approximate Numeric Data 611

Date and Time Data 613

date 613

time [(precision)] 613

smalldatetime 614

datetime 614

datetime2 [(precision)] 615

datetimeoffset [(precision)] 615

Discussion on All Date Types 616