Book Image

Hands-On Domain-Driven Design with .NET Core

By : Alexey Zimarev
5 (1)
Book Image

Hands-On Domain-Driven Design with .NET Core

5 (1)
By: Alexey Zimarev

Overview of this book

Developers across the world are rapidly adopting DDD principles to deliver powerful results when writing software that deals with complex business requirements. This book will guide you in involving business stakeholders when choosing the software you are planning to build for them. By figuring out the temporal nature of behavior-driven domain models, you will be able to build leaner, more agile, and modular systems. You’ll begin by uncovering domain complexity and learn how to capture the behavioral aspects of the domain language. You will then learn about EventStorming and advance to creating a new project in .NET Core 2.1; you’ll also and write some code to transfer your events from sticky notes to C#. The book will show you how to use aggregates to handle commands and produce events. As you progress, you’ll get to grips with Bounded Contexts, Context Map, Event Sourcing, and CQRS. After translating domain models into executable C# code, you will create a frontend for your application using Vue.js. In addition to this, you’ll learn how to refactor your code and cover event versioning and migration essentials. By the end of this DDD book, you will have gained the confidence to implement the DDD approach in your organization and be able to explore new techniques that complement what you’ve learned from the book.
Table of Contents (14 chapters)

Why Domain-Driven Design?

The software industry appeared back in the early 1960s and has been growing ever since. There have been predictions that one day all software will be written and software developers will no longer be needed, but this prophecy has never become reality, and the growing army of software engineers is working hard to satisfy the continually increasing demand.

However, from the very early days of the industry, the number of projects that were delivered very late and massively over budget, plus the number of failed projects, was overwhelming. The 2015 CHAOS report by the Standish Group ( suggests that from 2011 to 2015, the percentage of successful IT projects remained unchanged at a level of just 22%. Over 19% of projects failed, and the rest experienced challenges. Although the report might set somewhat controversial expectations for project success, it still paints a picture that is familiar to many. These numbers are astonishing. Over four decades, a lot of methods have been developed and advertised as silver bullets for software project management, but there has been little or no change in the number of successful projects.

One of the critical factors that define the success of any IT project is understanding the problem that the system is supposed to solve. We are all very familiar with systems that do not solve the problems they claim to answer or do it very inefficiently. Both the SCRUM and XP software development methodologies embrace interacting with users and understanding their problems.

The term Domain-Driven Design (DDD) was coined by Eric Evans in his now-iconic book Domain-Driven Design: Tackling Complexity in the Heart of Software published by Addison-Wesley back in 2004. More than a decade after the book was published, interest in the practices and principles described in the book started to grow exponentially. Many factors influenced this growth in popularity, but the most important one is that DDD explains how people from the software industry can build an understanding of their users' needs and create software systems that solve the problem and make an impact.

In this chapter, we will discuss how understanding the business domain, building domain knowledge, and distinguishing essential complexity from accidental complexity can help in creating software that matters.

The objective of this chapter is to explore the following topics:

  • Problem space versus solution space
  • What went wrong with requirements
  • Understanding complexity
  • The role of knowledge in software development