Part 3. Diving into the Java Persistence API (JPA)

The goal of this part is to provide deep and broad coverage of JPA in a digestible manner. After reading this part of the book, you will have all the knowledge necessary to start developing robust business applications using JPA.

Chapter 7, “Implementing domain models,” covers domain modeling, a central concept in ORM. The chapter describes how a conceptual business application domain model is translated to JPA entities, embedded objects, and entity relationships.

Chapter 8, “Object-relational mapping,” takes on the most complicated aspects of ORM: mapping entities, embedded objects, and entity relationships to databases. The chapter covers the annotations you can use for mapping objects to tables and fields to table columns. It also explores mapping various data types, primary keys, relationships, and OO inheritance to databases.

Chapter 9, “Manipulating entities with EntityManager,” describes the JPA EntityManager, a central interface that defines persistence operations. You’ll learn how the EntityManager interface is used to create, update, delete, and retrieve entities persisted in the database. The chapter also deals with the entity lifecycle as it relates to ORM persistence operations.

Chapter 10, “Using the query API and JPQL to retrieve entities,” covers object-relational queries. The chapter explores the use of the JPA query interface in detail. In addition, the chapter outlines how the Java Persistence Query Language (JPQL) is used to retrieve entities from the database in an extremely flexible and robust manner.