Spring Data JPA Implementation

Purpose

Use this skill when the task is specifically about persistence design or implementation in a Spring Boot codebase. This skill adds value through aggregate-root guidance, query-pattern selection, CQRS read-model decisions, and the bundled repository and relationship templates.

Critical rules

• Never create repositories for every entity. Create repositories only for aggregate roots.
• Never rely on long derived query method names when the query has become non-trivial.
• Never use save() blindly when entity state transitions matter; understand persist versus merge behavior.
• Prefer projections or dedicated query services for read-heavy paths.
• Keep transaction boundaries in the service layer unless the existing architecture intentionally does otherwise.

Workflow

Step 1: Identify the persistence problem

Collect the minimum context first: