MACIEJWALKOWIAK THE STATE OF JAVA RELATIONAL PERSISTENCE Maciej Walkowiak

MACIEJWALKOWIAK SF 2009, FIRST NO SQL MEETUP

MACIEJWALKOWIAK Relational databases give you too much. They force you to twist your object data to fit a RDBMS… NoSQL-based alternatives "just give you what you need". Jon Travis, principal engineer at SpringSource

MACIEJWALKOWIAK ! SCALABILITY "INFLEXIBILITY

MACIEJWALKOWIAK PostgreSQL • almost eliminated need for table locks • JSON data type support • geospatial queries • full text search

MACIEJWALKOWIAK MySQL • foreign keys • ACID (yay) • since 8.0 - JSON support • suitable for serious projects

MACIEJWALKOWIAK AWS Aurora • “the relational database for the cloud” • 10x faster than MySQL • db.x1e.32large has 128 vCPUs and 3904GB RAM • serverless

MACIEJWALKOWIAK RELATIONAL DATABASES ARE MORE FORGIVING

MACIEJWALKOWIAK

MACIEJWALKOWIAK MACIEJ WALKOWIAK - independent consultant - Open Source contributor

MACIEJWALKOWIAK MACIEJ WALKOWIAK - independent consultant - Open Source contributor

MACIEJWALKOWIAK

MACIEJWALKOWIAK https:/ /youtube.com/c/springacademy

MACIEJWALKOWIAK THE STATE OF JAVA RELATIONAL PERSISTENCE

MACIEJWALKOWIAK THE STATE OF JAVA RELATIONAL PERSISTENCE JDBC JPA HIBERNATE SPRING DATA R2DBC JOOQ JDBI FLYWAY DATABASE RIDER TEST CONTAINERS

MACIEJWALKOWIAK LET’S CLARIFY SOME BASICS

MACIEJWALKOWIAK

MACIEJWALKOWIAK

MACIEJWALKOWIAK network

MACIEJWALKOWIAK network select * from orders where id = 10

MACIEJWALKOWIAK network select * from orders where id = 10 JDBC Driver

MACIEJWALKOWIAK

MACIEJWALKOWIAK network JDBC Driver select * from orders where id = 10

MACIEJWALKOWIAK network Employee emp = new Employee(“Maria”); database.save(emp); JDBC Driver

MACIEJWALKOWIAK network Employee emp = new Employee(“Maria”); database.save(emp); JDBC Driver

MACIEJWALKOWIAK network Employee emp = new Employee(“Maria”); database.save(emp); JDBC Driver JPA

MACIEJWALKOWIAK JPA IS SIMPLE ..?

MACIEJWALKOWIAK class Order { private Long id; private Set items; } class OrderItem { private Long id; private int quantity; private Product product; } class Product { private Long id; private String name; }

MACIEJWALKOWIAK @Entity class Order { @Id @GeneratedValue private Long id; @OneToMany private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; }

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; }

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; } Product product1 = productRepostory.save( new Product("Accelerate")); Product product2 = productRepostory.save( new Product("Lean Enterprise")); Order order = new Order(); order.addItem(product1, 1); order.addItem(product2, 2); orderRepostory.save(order);

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; } Product product1 = productRepostory.save( new Product("Accelerate")); Product product2 = productRepostory.save( new Product("Lean Enterprise")); Order order = new Order(); order.addItem(product1, 1); order.addItem(product2, 2); orderRepostory.save(order); org.springframework.dao.InvalidDataAccessApiUsageException: org.hibernate.TransientObjectException: object references an unsaved transient instance - save the transient instance before flushing: com.maciejwalkowiak.springio.ordersjpa.OrderItem;

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; } Product product1 = productRepostory.save( new Product("Accelerate")); Product product2 = productRepostory.save( new Product("Lean Enterprise")); Order order = new Order(); order.addItem(product1, 1); order.addItem(product2, 2); orderRepostory.save(order); #

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; }

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name;

MACIEJWALKOWIAK #AskVlad

MACIEJWALKOWIAK #AskVlad

MACIEJWALKOWIAK #AskVlad So, the bidirectional @OneToMany association is the best way to map a one-to-many database relationship when we really need the collection on the parent side of the association.

MACIEJWALKOWIAK #AskVlad

MACIEJWALKOWIAK #AskVlad as a Service

MACIEJWALKOWIAK #AskVlad as a Service

MACIEJWALKOWIAK io.hypersistence hypersistence-optimizer 1.1.1-SNAPSHOT

MACIEJWALKOWIAK io.hypersistence hypersistence-optimizer 1.1.1-SNAPSHOT @RunWith(SpringRunner.class) @SpringBootTest public class OrdersJpaApplicationTests { @PersistenceContext private EntityManager entityManager; @Test public void testOptimizer() { final ListEventHandler listEventListener = new ListEventHandler(); new HypersistenceOptimizer( new JpaConfig(entityManager.getEntityManagerFactory()) .setEventHandler(new ChainEventHandler( Arrays.asList(listEventListener, LogEventHandler.INSTANCE) )) ).init(); } }

MACIEJWALKOWIAK CRITICAL - UnidirectionalOneToManyEvent - The [items] one-to-many association in the [com.maciejwalkowiak.springio.ordersjpa.Order] entity is unidirectional and does not render very efficient SQL statements. Consider using a bidirectional one-to-many association instead. For more info about this event, check out this User Guide link - https:// vladmihalcea.com/hypersistence-optimizer/docs/user-guide/#UnidirectionalOneToManyEvent CRITICAL - EagerFetchingEvent - The [product] attribute in the [com.maciejwalkowiak.springio.ordersjpa.OrderItem] entity uses eager fetching. Consider using a lazy fetching which, not only that is more efficient, but it is way more flexible when it comes to fetching data. For more info about this event, check out this User Guide link - https://vladmihalcea.com/hypersistence-optimizer/docs/user-guide/#EagerFetchingEvent MAJOR - SkipAutoCommitCheckEvent - You should set the [hibernate.connection.provider_disables_autocommit] configuration property to [true] while also making sure that the underlying DataSource is configured to disable the auto-commit flag whenever a new Connection is being acquired. For more info about this event, check out this User Guide link - https://vladmihalcea.com/hypersistence-optimizer/docs/user-guide/ #SkipAutoCommitCheckEvent

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name;

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; • which entity should have corresponding repository?

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; • which entity should have corresponding repository? • should OrderItem have a reference to product?

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; • which entity should have corresponding repository? • should OrderItem have a reference to product? • should OrderItem have a reference to Order?

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; • which entity should have corresponding repository? • should OrderItem have a reference to product? • should OrderItem have a reference to Order?

MACIEJWALKOWIAK JDBC JPA HIBERNATE SPRING DATA R2DBC JOOQ JDBI FLYWAY DATABASE RIDER TEST CONTAINERS

MACIEJWALKOWIAK

MACIEJWALKOWIAK PUBLISHING DOMAIN EVENTS FROM AGGREGATE ROOTS WITH SPRING DATA

MACIEJWALKOWIAK void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); } @Entity @Table(name = "orders") class Order { … public void confirmed() { this.status = OrderStatus.CONFIRMED; } }

MACIEJWALKOWIAK void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); mailSender.sendConfirmOrderEmail(order.getId()); }

MACIEJWALKOWIAK void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); mailSender.sendConfirmOrderEmail(order.getId()); pushNotifications.notifyCustomer(order.getId()); }

MACIEJWALKOWIAK class OrderConfirmed { private final Long orderId; … } private ApplicationEventPublisher eventPublisher; void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); eventPublisher .publishEvent(new OrderConfirmed(order.getId())); }

MACIEJWALKOWIAK @Component public class PushNotifications { @EventListener void handle(OrderConfirmed event) { LOGGER.info("Confirmed", event); } } @Component public class MailSender { @EventListener void handle(OrderConfirmed event) { LOGGER.info("Confirmed", event); } }

MACIEJWALKOWIAK class OrderConfirmed { private final Long orderId; … } private ApplicationEventPublisher eventPublisher; void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); eventPublisher .publishEvent(new OrderConfirmed(order.getId())); }

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order extends AbstractAggregateRoot { public void confirmed() { this.status = OrderStatus.CONFIRMED; registerEvent(new OrderConfirmed(id)); } }

MACIEJWALKOWIAK void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); eventPublisher .publishEvent(new OrderConfirmed(order.getId())); }

MACIEJWALKOWIAK void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); } MACIEJWALKOWIAK

MACIEJWALKOWIAK void confirmOrder(Long orderId) { Order order = orderRepostory.findById(orderId) .orElseThrow(() -> …); order.confirmed(); orderRepostory.save(order); } MACIEJWALKOWIAK

MACIEJWALKOWIAK

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items = new HashSet<>(); void addItem(Product product, int quantity) { this.items.add(new OrderItem(quantity, product)); } int sumQuantities() { return this.items .stream() .mapToInt(OrderItem::getQuantity) .sum(); } }

MACIEJWALKOWIAK select order0_.id as id1_1_ from orders order0_ select items0_.order_id as order_id4_0_0_, items0_.id as id1_0_0_, items0_.id as id1_0_1_, items0_.product_id as product_3_0_1_, items0_.quantity as quantity2_0_1_, product1_.id as id1_2_2_, product1_.name as name2_2_2_ from order_item items0_ left outer join product product1_ on items0_.product_id=product1_.id where items0_.order_id=? select items0_.order_id as order_id4_0_0_, items0_.id as id1_0_0_, items0_.id as id1_0_1_, items0_.product_id as product_3_0_1_, items0_.quantity as quantity2_0_1_, product1_.id as id1_2_2_, product1_.name as name2_2_2_ from order_item items0_ left outer join product product1_ on items0_.product_id=product1_.id where items0_.order_id=? select items0_.order_id as order_id4_0_0_, items0_.id as id1_0_0_, items0_.id as id1_0_1_, items0_.product_id as product_3_0_1_, items0_.quantity as quantity2_0_1_, product1_.id as id1_2_2_, product1_.name as name2_2_2_ from order_item items0_ left outer join product product1_ on items0_.product_id=product1_.id where items0_.order_id=?

MACIEJWALKOWIAK select order0_.id as id1_1_ from orders order0_ select items0_.order_id as order_id4_0_0_, items0_.id as id1_0_0_, items0_.id as id1_0_1_, items0_.product_id as product_3_0_1_, items0_.quantity as quantity2_0_1_, product1_.id as id1_2_2_, product1_.name as name2_2_2_ from order_item items0_ left outer join product product1_ on items0_.product_id=product1_.id where items0_.order_id=? select items0_.order_id as order_id4_0_0_, items0_.id as id1_0_0_, items0_.id as id1_0_1_, items0_.product_id as product_3_0_1_, items0_.quantity as quantity2_0_1_, product1_.id as id1_2_2_, product1_.name as name2_2_2_ from order_item items0_ left outer join product product1_ on items0_.product_id=product1_.id where items0_.order_id=? select items0_.order_id as order_id4_0_0_, items0_.id as id1_0_0_, items0_.id as id1_0_1_, items0_.product_id as product_3_0_1_, items0_.quantity as quantity2_0_1_, product1_.id as id1_2_2_, product1_.name as name2_2_2_ from order_item items0_ left outer join product product1_ on items0_.product_id=product1_.id where items0_.order_id=? select order_id, sum(quantity) from order_item group by order_id;

MACIEJWALKOWIAK HIBERNATE & JPA IS NOT THE ALTERNATIVE TO SQL. SQL IS YOUR FRIEND.

MACIEJWALKOWIAK @Entity @Table(name = "orders") @SqlResultSetMapping( name = "Order.getOrdersWithQuantity", classes = { @ConstructorResult( targetClass = OrderWithQuantity.class, columns = { @ColumnResult(name = "orderId"), @ColumnResult(name = "quantity") } ) } ) @NamedNativeQuery(name = "Order.getOrdersWithQuantity", query = "select order_id as orderId, " + "sum(quantity) as quantity " + "from order_item " + "group by id") class Order extends AbstractAggregateRoot { … }

MACIEJWALKOWIAK interface OrderRepository extends CrudRepository { @Query(value = "select order_id as orderId, " + "sum(quantity) as quantity " + "from order_item " + "group by id", nativeQuery = true) List findOrdersWithQuantity(); } interface OrderWithQuantity { Long getOrderId(); int getQuantity(); }

MACIEJWALKOWIAK

MACIEJWALKOWIAK List searchForProperties(SearchCriteria searchCriteria) { Set conditions = new HashSet<>(); if (searchCriteria.getPrice() != null) { if (searchCriteria.getPrice().getMin() != null) { conditions.add("price > :priceMin"); } if (searchCriteria.getPrice().getMax() != null) { conditions.add("price < :priceMax"); } } String query = "select * from property_ad where " + conditions.stream() .collect(Collectors.joining(" AND ")); Query q = entityManager.createNativeQuery(query, PropertyAd.class); if (searchCriteria.getPrice() != null) { if (searchCriteria.getPrice().getMin() != null) { q.setParameter("priceMin", searchCriteria.getPrice().getMin()); } if (searchCriteria.getPrice().getMax() != null) { q.setParameter("priceMax", searchCriteria.getPrice().getMax()); } } return q.getResultList(); }

MACIEJWALKOWIAK

MACIEJWALKOWIAK jOOQ generates Java code from your database and lets you build type safe SQL queries through its fluent API.

MACIEJWALKOWIAK • is not an ORM • is not a Spring Data project • is a library for building type-safe SQL queries in Java • it’s great for reading data from the database JOOQ

MACIEJWALKOWIAK select order_id, sum(quantity) from order_item group by order_id;

MACIEJWALKOWIAK dslContext.select(ORDER_ITEM.ORDER_ID, sum(ORDER_ITEM.QUANTITY)) .from(ORDER_ITEM) .where() .groupBy(ORDER_ITEM.ORDER_ID) .fetchInto(JooqOrderWithQuantity.class); select order_id, sum(quantity) from order_item group by order_id;

MACIEJWALKOWIAK List searchForProperties(SearchCriteria searchCriteria) { Set conditions = new HashSet<>(); if (searchCriteria.getPrice() != null) { if (searchCriteria.getPrice().getMin() != null) { conditions.add("price > :priceMin"); } if (searchCriteria.getPrice().getMax() != null) { conditions.add("price < :priceMax"); } } String query = "select * from property_ad where " + conditions.stream() .collect(Collectors.joining(" AND ")); Query q = entityManager.createNativeQuery(query, PropertyAd.class); if (searchCriteria.getPrice() != null) { if (searchCriteria.getPrice().getMin() != null) { q.setParameter("priceMin", searchCriteria.getPrice().getMin()); } if (searchCriteria.getPrice().getMax() != null) { q.setParameter("priceMax", searchCriteria.getPrice().getMax()); } } return q.getResultList(); }

MACIEJWALKOWIAK List searchForProperties(SearchCriteria searchCriteria) { Set conditions = new HashSet<>(); if (searchCriteria.getPrice() != null) { if (searchCriteria.getPrice().getMin() != null) { conditions.add(PROPERTY_AD.PRICE.gt(searchCriteria.getPrice().getMin())); } if (searchCriteria.getPrice().getMax() != null) { conditions.add(PROPERTY_AD.PRICE.lt(searchCriteria.getPrice().getMax())); } } return dslContext.selectFrom(PROPERTY_AD) .where(conditions) .fetchInto(PropertyAd.class); }

MACIEJWALKOWIAK WHERE TO START? • http:/ /www.jooq.org/ • https:/ /www.youtube.com/watch?v=j5QqHSIEcPE - Spring Tips: JOOQ • https:/ /www.youtube.com/watch?v=4pwTd6NEuN0 
 - Database centric applications with Spring Boot and jOOQ - Michael Simons • https:/ /start.spring.io/ - and select JOOQ starter

MACIEJWALKOWIAK SPRING DATA JDBC

MACIEJWALKOWIAK SPRING DATA JDBC Jens Schauder, Spring Data Team • simple ORM • embraces Domain Driven Design

MACIEJWALKOWIAK @Entity @Table(name = "orders") class Order { @Id @GeneratedValue private Long id; @OneToMany(cascade = CascadeType.ALL) @JoinColumn(name = "order_id") private Set items; } @Entity class OrderItem { @Id @GeneratedValue private Long id; private int quantity; @ManyToOne private Product product; } @Entity class Product { @Id @GeneratedValue private Long id; private String name; @Table("orders") class Order { @Id private Long id; private Set items; private OrderStatus status; } class OrderItem { @Id private Long id; private int quantity; private Long productId; } class Product { @Id private Long id; private String name; }

MACIEJWALKOWIAK @Table("orders") class Order { @Id private Long id; private Set items; private OrderStatus status; } class OrderItem { @Id private Long id; private int quantity; private Long productId; } class Product { @Id private Long id; private String name; }

MACIEJWALKOWIAK interface ProductRepository extends CrudRepository {} interface OrderRepository extends CrudRepository {}

MACIEJWALKOWIAK interface ProductRepository extends CrudRepository {} interface OrderRepository extends CrudRepository { Iterable findByStatus(OrderStatus status); }

MACIEJWALKOWIAK interface ProductRepository extends CrudRepository {} interface OrderRepository extends CrudRepository { @Query("select * from orders where status = :status") Iterable findByStatus(@Param("status") OrderStatus status); }

MACIEJWALKOWIAK interface ProductRepository extends CrudRepository {} interface OrderRepository extends CrudRepository { @Query("select * from orders where status = :status") Iterable findByStatus(@Param("status") OrderStatus status); } @Transactional void confirm(Long orderId) { Order order = orderRepository.findById(orderId) .orElseThrow(() -> new OrderNotFoundException(orderId)); order.confirmed(); orderRepository.save(order); }

MACIEJWALKOWIAK interface ProductRepository extends CrudRepository {} interface OrderRepository extends CrudRepository { @Query("select * from orders where status = :status") Iterable findByStatus(@Param("status") OrderStatus status); } @Transactional void confirm(Long orderId) { Order order = orderRepository.findById(orderId) .orElseThrow(() -> new OrderNotFoundException(orderId)); order.confirmed(); orderRepository.save(order); }

MACIEJWALKOWIAK @Table("orders") class Order extends AbstractAggregateRoot { @Id private Long id; private Set items = new HashSet<>(); private OrderStatus status; public void confirmed() { this.status = OrderStatus.CONFIRMED; registerEvent(new OrderConfirmed(id)); } }

MACIEJWALKOWIAK • No dirty tracking, lazy loading • No caching • No Many to One and Many to Many WHAT IS MISSING?

MACIEJWALKOWIAK • Simplicity • Predictibility • Embraces SQL • Enforced good design … BUT INSTEAD YOU GET

MACIEJWALKOWIAK SPRING DATA JDBC

MACIEJWALKOWIAK SPRING DATA JDBC BASED ON JDBC

MACIEJWALKOWIAK SPRING DATA JDBC BASED ON JDBC BLOCKING

MACIEJWALKOWIAK R2DBC REACTIVE RELATIONAL DATABASE CONNECTIVITY

MACIEJWALKOWIAK Mono count = Mono.from(connectionFactory.create()) .flatMapMany(it -> it.createStatement( "INSERT INTO legoset (id, name, manual) " + "VALUES($1, $2, $3)") .bind("$1", 42055) .bind("$2", "Description") .bindNull("$3", Integer.class) .execute()) .flatMap(io.r2dbc.spi.Result::getRowsUpdated) .next(); Flux> rows = Mono.from(connectionFactory.create()) .flatMapMany(it -> it.createStatement( "SELECT id, name, manual FROM legoset").execute()) .flatMap(it -> it.map((row, rowMetadata) -> collectToMap(row, rowMetadata))); R2DBC SPI

MACIEJWALKOWIAK R2dbc r2dbc = new R2dbc(connectionFactory); Flux count = r2dbc.inTransaction(handle -> handle.createQuery( "INSERT INTO legoset (id, name, manual) " + "VALUES($1, $2, $3)") .bind("$1", 42055) .bind("$2", "Description") .bindNull("$3", Integer.class) .mapResult(io.r2dbc.spi.Result::getRowsUpdated)); Flux> rows = r2dbc .inTransaction(handle -> handle.select( "SELECT id, name, manual FROM legoset") .mapRow((row, rowMetadata) -> collectToMap(row, rowMetadata)); } R2DBC API

MACIEJWALKOWIAK DatabaseClient databaseClient = DatabaseClient.create(connectionFactory); Mono count = databaseClient.execute() .sql( "INSERT INTO legoset (id, name, manual) " + "VALUES($1, $2, $3)") .bind("$1", 42055) .bind("$2", "Description") .bindNull("$3", Integer.class) .fetch() .rowsUpdated(); Flux> rows = databaseClient.execute() .sql("SELECT id, name, manual FROM legoset") .fetch() .all(); SPRING DATA R2DBC

MACIEJWALKOWIAK class LegoSet { @Id private Integer id; private String name; private String manual; } interface LegoSetRepostory extends ReactiveCrudRepository {} Mono legoSet = legoSetRepository.save(new LegoSet(42055, "Some name", null)); Flux allSets = legoSetRepository.findAll(); SPRING DATA R2DBC

MACIEJWALKOWIAK • Alpha stage • PostgreSQL, MySQL, MSSQL, H2 • Plays nice with JOOQ R2DBC

MACIEJWALKOWIAK HOW CAN WE TEST IT?

MACIEJWALKOWIAK HOW CAN WE TEST IT? TESTCONTAINERS

MACIEJWALKOWIAK org.testcontainers postgresql 1.11.2 test

MACIEJWALKOWIAK org.testcontainers postgresql 1.11.2 test 
 
 spring.datasource.driver-class-name=org.testcontainers.jdbc.ContainerDatabaseDriver spring.datasource.url=jdbc:tc:postgresql:9.6.8://hostname/databasename spring.test.database.replace=none

MACIEJWALKOWIAK org.testcontainers postgresql 1.11.2 test 
 
 spring.datasource.driver-class-name=org.testcontainers.jdbc.ContainerDatabaseDriver spring.datasource.url=jdbc:tc:postgresql:9.6.8://hostname/databasename spring.test.database.replace=none 
 @RunWith(SpringRunner.class) @DataJdbcTest public class OrderRepositoryTest { @Autowired private OrderRepository orderRepository; @Test public void foo() { System.out.println(orderRepository.findAll()); } }

MACIEJWALKOWIAK org.testcontainers postgresql 1.11.2 test 
 
 spring.datasource.driver-class-name=org.testcontainers.jdbc.ContainerDatabaseDriver spring.datasource.url=jdbc:tc:postgresql:9.6.8://hostname/databasename spring.test.database.replace=none 
 @RunWith(SpringRunner.class) @DataJdbcTest public class OrderRepositoryTest { @Autowired private OrderRepository orderRepository; @Test public void foo() { System.out.println(orderRepository.findAll()); } }

MACIEJWALKOWIAK KEY TAKEAWAYS • There is a world beyond JPA • Embrace SQL • Consider Spring Data JDBC • Watch R2DBC progress • Use TestContainers!

MACIEJWALKOWIAK THANK YOU! https:/ /youtube.com/c/springacademy https:/ /twitter.com/maciejwalkowiak https:/ /maciejwalkowiak.com http:/ /speakerdeck.com/maciejwalkowiak