This chapter uses the same data model used in Chapter 8, Adding Reporting Capabilities. The data model is based on a simple SQL table, Call. We'll use JPA to connect to a file-based H2 database. The JPA logic is encapsulated in a CallRepository class. For more details about the data model, please refer to Chapter 8, Adding Reporting Capabilities.
You can find the complete source code of this chapter's example in the Data-centric-Applications-with-Vaadin-8chapter-09 Maven project of the source code that accompanies this book.