The goal of this document is to discuss how to map an application's domain model to a relational database.

Historically applications using Hibernate would have used its proprietary XML mapping file format for this purpose. With the coming of JPA, most of this information is now defined in a way that is portable across ORM/JPA providers using annotations (and/or standardized XML format). This document will focus on JPA mapping where possible. For Hibernate mapping features not supported by JPA we will prefer Hibernate extension annotations, again where possible.