Implementing Domain-Driven Design

Use Case Optimal Repository Queries

Rather than reading multiple whole Aggregate instances of various types and then programmatically composing them into a single container (DTO or DPO), you might instead use what is called a use case optimal query. This is where you design your Repository with finder query methods that compose a custom object as a superset of one or more Aggregate instances. The query dynamically places the results into a Value Object (6) specifically designed to address the needs of the use case. You design a Value Object, not a DTO, because the query is domain specific, not application specific (as are DTOs). The custom use case optimal Value Object is then consumed directly by the view renderer.

The use case optimal query ...