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

To comprehend how software may be implemented based on hexagonal architecture, let us review an example regarding a restaurant.

## Example definition
This restaurant wants to allow a customer to order something by using its website. The website consumes **Rest APIs** to execute the business logic. Therefore it is necessary to implement a microservice that exposes the functionality to create an order. This use case has the following restriction:
* If a customer has no created orders, it is possible to create a new one
* If a customer has already created orders, it is not possible to create a new one


### Model definition
The following diagram depicts the domain layer and what domain objects should be implemented to accomplish the business rules.


To comprehend how software may be implemented based on hexagonal architecture, let us review an example regarding a restaurant.

# Example definition
This restaurant wants to allow a customer to order something by using its website. The website consumes **Rest APIs** to execute the business logic. Therefore it is necessary to implement a microservice that exposes the functionality to create an order. This use case has the following restriction:
* If a customer has no created orders, it is possible to create a new one
* If a customer has already created orders, it is not possible to create a new one


## Model definition
The following diagram depicts the domain layer and what domain objects should be implemented to accomplish the business rules.


Learn what the domain layer in hexagonal architecture is and how to implement it.

Introduction

Mapping Domain to Model

Domain Activities

Domain Objects

Domain Abstractions

Hexagonal Architecture

Domain Layer

Example definition