The purpose and use of aggregate patterns

The aggregate pattern is a specific software design pattern within DDD. It promotes the collection of related entities and aggregates them into a unit.

Aggregates make it easier to define ownership of elements in large systems. Without them, we run the risk of sprawling and trying to do too much. After we have identified the different contexts in the domain, we can then begin to extract the exact data we need from potentially multiple contexts and sources and model them.

Aggregates and aggregate roots

An aggregate comprises one or more entities and value object models that, in one way or another, interact. This interaction then encourages us to treat them as a unit for data changes. We also want to ensure that, at all times, there is consistency in the aggregate before making changes. In our concept of a healthcare management system, we have already scoped that we have a patient, who more than likely also has an address. A set of changes...