Repository Domain Types for Business Logic Entry Points

Goal

The types exchanged between business-logic entry points and repositories must be domain-entity types and domain value types.

Repository method signatures — parameters and return types — must use the domain model directly. They must not expose types that depend on or are generated by the concrete persistence technology in use.

This rule keeps the business-logic layer decoupled from persistence-technology details. The entry point works with domain entities and domain values; the repository handles the translation to and from the persistence representation internally.

What Counts as In Scope

Apply this skill to code that does one or more of these things:

• defines a repository interface or repository method signatures
• defines repository method parameters or return types
• passes persistence-technology types between a business-logic entry point and a repository
• returns ORM entities, database records, row objects, document models, or persistence-generated types from a repository to a business-logic entry point
• accepts persistence-technology types as input from a business-logic entry point into a repository