Domain Driven Design or DDD for short is a huge but interesting topic. It has many complex subjects focused on business and technical perspectives. In the technology industry, people always talk about how both perspectives should work together in order to give the business benefits. However, that is not an easy task and it is when DDD appears in the scene. In this course, you are going to learn the most important concepts of DDD. You will see some concerns, techniques to model, how DDD can be implemented using hexagonal architecture and many other amazing concepts.

Domain Driven Design (DDD) Made Easy

When dealing with complex bounded context, perhaps it is necessary to create a huge number of entities and value objects, perhaps it is necessary to create interactions between them, and perhaps this situation may lead to creating a big ball of mud. As explained before, this is an anti-pattern where interactions among objects are unmanageable. It can be described as spaghetti code.

A big ball of mud implementation tends to grow out of control and obviously, it is difficult to maintain over time. Domain Driven Design understands this problem and solves it by defining a tactical pattern called Aggregate.

# What is an aggregate? 
An aggregate object is a cluster of entities and value objects that are treated as a single unit from the domain and data perspective. This object acts as a load balancer in terms of accessing a set of nodes. What it means is that an aggregate is the only access point for external objects. As the image below shows, an aggregate has clear bounds, and artifacts inside have no contact with the outside world:

Learn what aggregates are and their importance in the Domain Driven Design world.

Introduction

Mapping Domain to Model

Domain Activities

Domain Objects

Domain Abstractions

Hexagonal Architecture

Aggregates