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. Part of cursor-rules-java project license: Apache-2.0 metadata: author: Juan Antonio Breña Moral version: 0.15.0-SNAPSHOT

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

Workflow

1. Read reference and assess project context

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

1. Gather scope and decide target improvements

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

1. Apply framework-aligned changes

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

1. 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.