/512-frameworks-micronaut-data

name: 512-frameworks-micronaut-data
description: Use when you need data access with Micronaut Data — @MappedEntity, CrudRepository/PageableRepository, @Query with parameters, @Transactional services, projections, @Version, and @MicronautTest with TestPropertyProvider and Testcontainers. For raw java.sql access without generated repositories, use @511-frameworks-micronaut-jdbc. This should trigger for requests such as Review or implement Micronaut Data repositories and entities; Add transactions, pagination, or projections in Micronaut persistence layer; Model Micronaut Data entities and repositories; Review Micronaut Data transactions and pageable queries; Improve projections or optimistic locking with Micronaut Data. Part of Plinth Toolkit
license: Apache-2.0
metadata:
  author: Juan Antonio Breña Moral
  version: 0.18.0

Micronaut Data Guidelines

Apply Micronaut Data patterns for relational repositories and safe SQL.

**What is covered in this Skill?**

• @MappedEntity, @Id, @GeneratedValue, @MappedProperty for column mapping
• @Repository interfaces extending CrudRepository / PageableRepository
• Derived finder methods and @Query with named parameters
• @Transactional on @Singleton services (readOnly where appropriate)
• Page and Pageable for list endpoints
• DTO/interface projections for read-heavy queries
• @Version for optimistic locking
• Integration tests: @MicronautTest + TestPropertyProvider + Testcontainers

**Scope:** Apply recommendations based on the reference rules and good/bad code examples.

Constraints

Compile before persistence changes; verify the full build after.

• **MANDATORY**: Run `./mvnw compile` or `mvn compile` before applying any change
• **SAFETY**: If compilation fails, stop immediately
• **VERIFY**: Run `./mvnw clean verify` or `mvn clean verify` after applying improvements
• **BEFORE APPLYING**: Read the reference for detailed rules and examples
• **EDGE CASE**: If the user goal is ambiguous, stop and ask a clarifying question before editing files or running project-wide commands
• **EDGE CASE**: If required context, files, credentials, or tools are missing, report the blocker explicitly and ask whether to proceed with setup or fallback guidance
• **EDGE CASE**: If requested changes conflict with project constraints or safety boundaries, explain the conflict and ask for user confirmation on the preferred trade-off

When to use this skill

• Review or implement Micronaut Data repositories and entities
• Add transactions, pagination, or projections in Micronaut persistence layer
• Model Micronaut Data entities and repositories
• Review Micronaut Data transactions and pageable queries
• Improve projections or optimistic locking with Micronaut Data

Workflow

1. **Read reference and assess project context**

Read `references/512-frameworks-micronaut-data.md` and inspect the current project setup before proposing changes.

2. **Gather scope and decide target improvements**

Identify requested outcomes, constraints, and the minimum safe set of changes to apply.

3. **Apply framework-aligned changes**

Implement or refactor configuration/code following the reference patterns and project conventions.

4. **Run verification and report results**

Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions.

Reference

For detailed guidance, examples, and constraints, see [references/512-frameworks-micronaut-data.md](references/512-frameworks-micronaut-data.md).