Spring Data Jpa

Skill: spring-data-jpa

Type

core

Purpose

Provide a consistent persistence layer using Spring Data JPA for Spring Boot applications.

When to Use

Use when application data must be stored in a relational database and accessed through repositories.

Rules

• Keep persistence model separate from web model (DTO/form/view objects).
• Use @Entity classes for database mapping; do not use Java record for mutable JPA entities.
• Use Spring Data repository interfaces (JpaRepository) for aggregate access.
• Keep transactional write orchestration in services (@Transactional on service methods), not controllers.
• Avoid exposing entities directly in HTML/API contracts.
• Prefer explicit fetch and query design; avoid accidental N+1 query patterns in list/detail flows.

Defaults

• Package entities and repositories by feature area.
• Persist enums explicitly with stable mapping (EnumType.STRING when applicable).
• Use optimistic locking (@Version) for entities with concurrent write risk.
• Keep schema lifecycle managed by migrations (Flyway), not ad-hoc runtime schema generation.

Validation Checklist

Before finishing:

• Entity boundaries are separate from form/request objects.
• Repository interfaces are focused on aggregate use cases.
• Write operations execute inside service-layer transactions.
• Read-heavy endpoints are checked for query efficiency.

Anti-Patterns

• Do NOT place persistence logic in controllers/templates.
• Do NOT rely on spring.jpa.hibernate.ddl-auto=update in production-like profiles.
• Do NOT use database entities as direct response/view contracts.
• Do NOT leave transaction boundaries implicit for multi-step writes.