Micronaut JDBC — programmatic SQL

Apply programmatic JDBC patterns in Micronaut with safe SQL and clear transactions.

What is covered in this Skill?

• Injected javax.sql.DataSource (Hikari-backed with micronaut-jdbc-hikari) and try-with-resources for Connection / PreparedStatement
• PreparedStatement with bind parameters — never string concatenation
• Mapping ResultSet rows to Java records (dedicated mapRow method)
• Safe single-row queries with Optional; never assume rs.next() succeeds
• SQLException translation to domain exceptions (catch-translate-rethrow)
• Streaming large result sets with setFetchSize to avoid OOM
• Batch updates with addBatch / executeBatch for bulk inserts
• @Transactional service boundaries and TransactionDefinition.Propagation (e.g. REQUIRES_NEW for independent commits)
• Self-invocation pitfall: call transactional collaborators through injected beans, not this.method()
• SQL text blocks for multi-line SQL (upserts, dialect-specific clauses)
• When to prefer Micronaut Data (@512) vs raw JDBC

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