Implementing Domain-Driven Design

Identity

Let’s clarify the reasons for assigning unique identity. At times it may be necessary to distinguish Events one from another, but the need may be rare. In the Bounded Context where the Event is caused, created, and published, there will tend to be little reason to compare one Event to another, if ever. But what if, for some reason, Events must be compared? And what if an Event is designed as an Aggregate?

It may be enough to allow Event identity to be represented by its properties, as is the case with Value Objects. The Event’s name/type along with the identities of the Aggregate(s) involved in the cause, as well as a timestamp of when the Event occurred, may be enough to distinguish it from others.

In cases where an Event is modeled ...