A Spring GraphQL batch example to solve N + 1 problem.

Article - Spring for GraphQL: Mutation

Clone repository and do gradle build ./gradlew clean build.

Java version : Java 17

• resources/graphql/book.graphql contains schema of GraphQL API
• BooksCatalogController provides implementation of all GraphQL example
• domain.model contains domain model
• domain.repository contains Spring JPA implementation of repository. Repository is implemented using in memory H2 database
• domain.repository.model contains database representation domain model
• domain.repository.mapper contains classes which maps domain object to database object
• application.service package contains service classes
• resources\data.sql contains insert statements to bootstrap book and rating data so that Query returns some result without mutation

By default, the data.sql script executes before Hibernate initialization. As we're relying on Hibernate to create table, we need to set spring.jpa.defer-datasource-initialization=true For production application think of using tools like Flyway or Liquibase.