Quarkus JDBC — programmatic SQL

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

What is covered in this Skill?

• Injected javax.sql.DataSource (Agroal-backed) 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<T>; 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 propagation types (TxType.REQUIRES_NEW for independent commits)
• CDI self-invocation pitfall: always call transactional methods through the injected proxy
• Dev Services for databases in dev/test
• When to prefer Panache (@412) vs raw JDBC

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

Constraints

Compile before JDBC refactors; verify after changes.

• MANDATORY: Run ./mvnw compile or mvn compile before applying any change
• PREREQUISITE: Project must compile before applying JDBC improvements
• SAFETY: If compilation fails, stop immediately
• BLOCKING CONDITION: Compilation errors must be resolved by the user before proceeding
• VERIFY: Run ./mvnw clean verify or mvn clean verify after applying improvements
• BEFORE APPLYING: Read the reference for detailed rules and examples

When to use this skill

• Review JDBC or SQL data access in a Quarkus project
• Improve transactions and parameter binding for Quarkus JDBC
• Translate SQLException to domain exceptions or stream large result sets
• Fix CDI self-invocation bypassing @Transactional in Quarkus

Reference

For detailed guidance, examples, and constraints, see references/411-frameworks-quarkus-jdbc.md.