Java Reference
In-Depth Information
EclipseLink JPA Persistence
Provider
The
Java
Persistence
API
(
JPA
) is a component of EJB 3.0 and replaces CMP and
JDO. Oracle's strategic Java persistence implementation within Oracle Fusion
Middleware 11
g
is Oracle TopLink 11
g
, which is based on the open source
EclipseLink. EclipseLink is based on an older version of TopLink, which Oracle
contributed to Eclipse. The EclipseLink version in Oracle Fusion Middleware
11
g
supports the JPA 1.0 specification. In this chapter, we shall discuss the JPA
framework and the EclipseLink JPA persistence provider.
What is a JPA persistence provider? A JPA persistence provider is an implementation
of the JPA; JPA is just a specification. Various JPA persistence providers such
as Hibernate, Apache OpenJPA, and JPA for WebSphere Application Server are
available, but we shall be discussing the persistence provider in Oracle Fusion
Middleware: the EclipseLink JPA persistence provider. This section is not meant to
be a repetition of the JPA specification (
http://jcp.org/en/jsr/detail?id=220
),
or the EclipseLink JPA documentation (
http://wiki.eclipse.org/Category:JPA
),
but a primer and an introduction to some of the features/values used in this topic. In
this chapter, we shall discuss the following:
• How to specify the EclipseLink persistence provider?
• The JPA framework
° The advantages of JPA
° What is required for JPA?
• Types of Entity Managers
° Container-managed entity manager
° Application-managed entity manager
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