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)

CQRS - The Read Side

In the previous chapter, we learned about persisting aggregates to different types of databases. However, we haven't looked at the topic of retrieving data from a database, except using the repository Load method to retrieve a single aggregate.

It is now time to get a hold on the data we managed to store in the database and add some GET endpoints to the API. For this book, I had no plans to show you how to build repositories with numerous GetByThat methods or, even worse, a generic repository that returns IQueryable<T>. That kind of approach, while it might seem attractive, removes the Ubiquitous Language from queries, since developers start to retrieve aggregates by filtering properties. For example, a query such as _repository.Query(x => x.State == State.IsActive && x.Price.Amount > 100) tells us very little about the intention of...