J2EE - JPA
Problems
Mismatches between relational and object models
What is JPA
Java Persistence API is a collection of classes and methods (interfaces/specification) to persistently store the vast amounts of data into a database which is provided by the Oracle Corporation.
JPA shows how to define a Plain Oriented Java Object (POJO) as an entity and how to manage entities with relations.
JPA Provider
- Hibernate
- Eclipselink
- Toplink
Difference between JPA and Hibernate
- JPA is just a specification, meaning there is no implementation. Hibernate is the Hibernate’s JPA implementation.
- JPA tells you how to dance, Hibernate is the dancer.
ORM Architecture
three phase: Object data -> Mapping -> Relational data
Spring JPA Example
- http://chennanni.github.io/note-tech/archive/spring/jpa/
- https://spring.io/guides/gs/accessing-data-jpa/
