Introduction

In this guide, you will find a collection of practical and illustrative examples that demonstrate how to apply tactical DDD principles to design and model complex domains effectively. Tactical DDD is a crucial aspect of DDD that focuses on the internal structure of your domain, providing solutions to common design challenges, enhancing code maintainability, and fostering a deep understanding of the domain itself.

In this document, you will discover:

• Value Objects: We will explore the concept of value objects and how they can be used to represent essential domain concepts that lack identity. You will see how value objects enhance code clarity, immutability, and data consistency.

• Entities: Learn how to model entities that have distinct identities and lifecycles within your domain. We will provide examples of how to define and manage these entities effectively.

• Aggregates: Aggregates are vital for maintaining data consistency within your domain. You will see how to define aggregates, manage their boundaries, and handle complex operations across multiple entities and value objects.

• Repositories: Gain insights into repositories and how they facilitate data access and persistence for your domain entities and aggregates.

• Domain Services: Discover the role of domain services and how they can encapsulate domain logic that doesn't naturally fit within entities or value objects.

• Factories: Learn how to create factories to handle the complex instantiation of domain objects, especially when object creation involves intricate processes or conditions.

• Domain Events: Explore how to use domain events to broadcast changes and events within your domain, allowing for decoupled communication between different parts of your application.

• Specifications: Understand how to create specifications that define criteria for selecting domain objects and filtering them according to specific conditions.

Throughout these examples, we will provide real-world scenarios and use cases, illustrating how tactical DDD principles can be applied in a practical and beneficial way. By the end of this document, you will have a clearer understanding of how to structure your code, design your domain, and ensure that your software solutions align closely with the problem space they are meant to address.

Whether you are new to Domain-Driven Design or looking to deepen your understanding of tactical DDD, this document will serve as a valuable resource to enhance your domain modeling skills and create more robust, maintainable, and effective software solutions. We hope you find these examples both educational and inspirational as you embark on your journey into the world of tactical DDD.