Spring Data R2DBC

Spring Data R2DBC provides repository support for the Reactive Relational Database Connectivity (R2DBC) API.

JPA works with JDBC. JDBC is fully blocking API.

Maven Dependencies

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-r2dbc</artifactId>
</dependency>

In terms of databases, Spring Data R2DBC requires a driver to abstract common SQL functionality over vendor-specific flavours. Support for the databases can be checked here (you need to add chosen driver as Maven Dependency).

Initializing Database

You can initialize Database with 🟢 DatabaseConfig:

@Configuration
public class DatabaseConfig {

    @Value("classpath:/schema.sql")
    Resource resource; (1)

    @Bean
    ConnectionFactoryInitializer connectionFactoryInitializer(ConnectionFactory connectionFactory) {
        ConnectionFactoryInitializer initializer = new ConnectionFactoryInitializer(); (2)
        initializer.setConnectionFactory(connectionFactory); (3)
        initializer.setDatabasePopulator(new ResourceDatabasePopulator(resource)); (4)
        return initializer;
    }

}

1	Database SQL script which will be used to create schema. The `schema.sql` is located under `src/main/resources`
2	`🟢 ConnectionFactoryInitializer` is used to set up a database during initialization and clean up a database during destruction.
3	`⚪ ConnectionFactory` is an R2DBC factory for creating connections and entry point for a driver.
4	`🟢 ResourceDatabasePopulator` populates, initializes, or cleans up a database using SQL scripts defined in external `⚪ Resource`.