Spring Data JDBC Basics Sample

This project is a compact Spring Boot application that demonstrates how to build and persist aggregate roots with Spring Data JDBC. It creates a simple orders domain composed of Order and LineItem entities backed by an in‑memory H2 database and prints formatted summaries to the console so you can quickly verify persistence behaviour.

Requirements

• Java 17+
• Maven 3.9+

Running the app

mvn spring-boot:run

During startup the app:

1. Recreates the in-memory schema defined in schema.sql and seeds sample data from data.sql.
2. Clears all persisted aggregates via OrderRepository.
3. Creates a new Order for “Alice” with two LineItems and saves it.
4. Prints the saved order, all orders, and the filtered list for Alice in an easy-to-read layout.

You should see console sections that look like:

-------- Saved Order --------
Order #3 for Alice
  * Spring in Action            x1  @   $39.90 ->   $39.90
  * Spring Data JDBC Guide      x2  @   $29.90 ->   $59.80
  Total: $99.70

Project structure

• JdbcBasicsApplication – Spring Boot launcher and demo CommandLineRunner that seeds and prints orders.
• domain/Order & domain/LineItem – Aggregate root and value objects with explicit column mappings for H2.
• domain/OrderRepository – Spring Data JDBC repository with derived and annotated queries.
• schema.sql / data.sql – Database schema and bootstrap data executed automatically on startup.
• application.properties – H2 datasource configuration and console toggle.

H2 console

You can inspect the in-memory database through the H2 console once the app is running:

• URL: http://localhost:8080/h2-console
• JDBC URL: jdbc:h2:mem:ordersdb
• User: sa
• Password: (leave blank)

Building an executable JAR

mvn clean package

The runnable artifact lands in target/spring-data-jdbc-basics-sample-0.0.1-SNAPSHOT.jar.

Next steps

• Swap in a persistent database by updating the datasource and removing the schema.sql/data.sql scripts.
• Expand the domain with additional aggregates or relationships to explore more Spring Data JDBC features.
• Add automated tests that exercise the repository and demo runner logic.