In the previous chapter, we went through the implementation process for a simple domain model. This model has one entity, several value objects, and domain services. The model represents just one area of our system, and we deliberately kept everything else out of scope. We discussed that the domain model project needs to be isolated from anything else and how domain services can be part of the model although their implementation can be done in the application layer. Now, we are going to learn about putting our domain model in action. So far we were not referencing the domain model from anywhere, which makes it rather useless. To start using the model in our application, we need to be able to call the model. In addition to that, we also need to be able to persist all changes that happen in the model, so we do not lose the system state.

The following topics will be covered in this chapter:

• Application layer - the outer edge of the onion architecture
• Calling the domain model from Web API
• Persisting the domain model changes