Java Reference
In-Depth Information
Interacting with
Databases through the
Java Persistence API
The Java Persistence API (JPA) is an object relational mapping API. Object relational
mapping tools help us automate mapping Java objects to relational database tables.
Earlier versions of J2EE used Entity Beans as the standard approach for object
relational mapping. Entity Beans attempted to keep the data in memory always
synchronized with database data, a good idea in theory, however, in practice this
feature resulted in poorly performing applications.
Several object relational mapping APIs were developed to overcome the limitations
of Entity Beans, such as Hibernate, iBatis, Cayenne, and Toplink among others.
With Java EE 5, Entity Beans were deprecated in favor of JPA. JPA took ideas from
several object relational mapping tools and incorporated them into the standard. As
we will see in this chapter NetBeans has several features that make development
with JPA a breeze.
The following topics will be covered:
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Creating our first JPA entity
Interacting with JPA entities with entity manager
Generating forms in JSF pages from JPA entities
Generating JPA entities from an existing database schema
JPA named queries and JPQL
Entity relationships
Generating complete JSF applications from JPA entities
