Preface xi

Acknowledgments xv

About the Author xvii

Chapter 1: DDD for Me 1

Will DDD Hurt? 2

Good, Bad, and Effective Design 3

Strategic Design 7

Tactical Design 8

The Learning Process and Refining Knowledge 9

Let’s Get Started! 10

Chapter 2: Strategic Design with Bounded Contexts and the Ubiquitous Language 11

Domain Experts and Business Drivers 17

Case Study 21

Fundamental Strategic Design Needed 25

Challenge and Unify 29

Developing a Ubiquitous Language 34

Architecture 41

Summary 44

Chapter 3: Strategic Design with Subdomains 45

What Is a Subdomain? 46

Types of Subdomains 46

Dealing with Complexity 47

Summary 50

Chapter 4: Strategic Design with Context Mapping 51

Kinds of Mappings 54

Making Good Use of Context Mapping 60

An Example in Context Mapping 70

Summary 73

Chapter 5: Tactical Design with Aggregates 75

Why Used 76

Aggregate Rules of Thumb 81

Modeling Aggregates 88

Summary 98

Chapter 6: Tactical Design with Domain Events 99

Designing, Implementing, and Using Domain Events 100

Event Sourcing 107

Summary 109

Chapter 7: Acceleration and Management Tools 111

Event Storming 112

Managing DDD on an Agile Project 125

Timeboxed Modeling 132

Summary 136

References 137

Index 139

Vaughn Vernon is a champion of simplifying software architecture and development, with an emphasis on reactive methods. He has a unique ability to teach and lead with Domain-Driven Design using lightweight tools to unveil unimagined value. He helps organizations achieve competitive advantages using enduring tools such as architectures, patterns, and approaches, and through partnerships between business stakeholders and software developers.

Domain-Driven Design (DDD) software modeling delivers powerful results in practice, not just in theory, which is why developers worldwide are rapidly moving to adopt it. Now, for the first time, there’s an accessible guide to the basics of DDD: What it is, what problems it solves, how it works, and how to quickly gain value from it. Concise, readable, and actionable, Domain-Driven Design Distilled never buries you in detail–it focuses on what you need to know to get results. Vaughn Vernon, author of the best-selling Implementing Domain-Driven Design, draws on his twenty years of experience applying DDD principles to real-world situations. He is uniquely well-qualified to demystify its complexities, illuminate its subtleties, and help you solve the problems you might encounter. Vernon guides you through each core DDD technique for building better software. You’ll learn how to segregate domain models using the powerful Bounded Contexts pattern, to develop a Ubiquitous Language within an explicitly bounded context, and to help domain experts and developers work together to create that language. Vernon shows how to use Subdomains to handle legacy systems and to integrate multiple Bounded Contexts to define both team relationships and technical mechanisms. Domain-Driven Design Distilled brings DDD to life. Whether you’re a developer, architect, analyst, consultant, or customer, Vernon helps you truly understand it so you can benefit from its remarkable power. Coverage includes What DDD can do for you and your organization–and why it’s so important The cornerstones of strategic design with DDD: Bounded Contexts and Ubiquitous Language Strategic design with Subdomains Context Mapping: helping teams work together and integrate software more strategically Tactical design with Aggregates and Domain Events Using project acceleration and management tools to establish and maintain team cadence