FreeBooks-by-Author List API

Complete an API built on Spring Boot 3 and JPA (in-memory H2) that returns authors together with the lists of books they wrote. It is a one-author-to-many-books relationship: for each author, the name and the titles of the books they wrote are grouped together and returned in a single response.

For an API that returns a list and the related data attached to each item, how that data is loaded can change the way the database is used a great deal even when the result is identical. The response may look fine on screen, yet the data-access approach reveals its differences as the data grows. This problem is a data-access exercise in how related data is loaded when serving a list over a one-to-many relationship.

What should you be mindful of when returning a list together with its related data?

Beyond whether the result is correct, look at how the database is accessed while producing that result. The same result can be produced through several different data-access approaches.

How do you verify the data-access approach, not just the result?

A test that only asserts the result data won't reveal differences in approach. This workspace includes a helper that counts the number of executed SQL statements, so you can check not just the result but how the lookups are carried out.