Spring Team: Jens Schauder

Spring Data JDBC, References, and Aggregates

September 24, 2018

In my previous blog article, I described how to set up and use Spring Data JDBC. I also described the premise of making Spring Data JDBC easier to understand than JPA. This becomes interesting once you consider references. As a first example, consider the following domain model:

class PurchaseOrder {

  private @Id Long id;
  private String shippingAddress;
  private Set<OrderItem> items = new HashSet<>();

  void addItem(int quantity, String product) {
    items.add(createOrderItem(quantity, product));
  }

  private OrderItem createOrderItem(int quantity, String product) {

    OrderItem item = new OrderItem();
    item.product = product;
    item.quantity = quantity;
    return item;
  }
}

Introducing Spring Data JDBC

Engineering

September 17, 2018

With the upcoming Lovelace GA release, we’re going to ship a new Spring Data Module: Spring Data JDBC.

The idea behind Spring Data JDBC is to provide access to relational databases without submitting to the complexities of JPA. JPA offers such features as lazy loading, caching, and dirty tracking. While these are great if you need them, they can actually make thinking about JPA and its behavior harder than it has to be.

Lazy loading might trigger expensive statements when you don’t expect it or it might fail with an exception. Caching can get in your way when you actually want to compare two versions of an entity and being dirty makes it hard to find a single point where all persistence operations pass through.