DDD Aggregate is responsible for encapsulating business logic for the component. But we need to be aware that when we are implementing business logic for a long time process that is coordinating many components, like subscription trial, we have another building block for this. It’s a process manager. Below I pointed out some differences between these two building blocks.

In most cases, I use UUID as an id for aggregate entity. But when it comes to big amount of entities in SQL DB it can become scalability problem to handle UUID as id. Here are some pros and cons of different approaches to entity ids.

So there is this legacy code.

Introducing branching in code (by feature toggle) is not the easiest practice but gives you some direct and some not direct benefits.

Post in answer to a StackOverflow questions “SQLAlchemy and DDD” and “Persist POJOs in Python using a DDD approach”.

Post in answer to a StackOverflow question. You can find code used in this example here.