JPA Tutorial

This section will describe you all the aspects of JPA such as what is JPA, architecture of JPA, features of JPA, JPA entities, entity inheritance JPA, how to manage entities in JPA, JPA querying entities.

JPA Tutorial

JPA Tutorial

In this section we will discuss about the Java Persistence API.

This section will describe you all the aspects of JPA such as what is JPA, architecture of JPA, features of JPA, JPA entities, entity inheritance JPA, how to manage entities in JPA, JPA querying entities.

What is JPA ?

JPA is also called Java Persistence API that facilitate developers to manage relational data using ORM (object/relational mapping). JPA, a standard persistence API is added since Java EE 5 specification. Initially JPA was introduced with EJB 3.0 under the JSR 220 specifications. JPA was introduced for simplifying the EJB entity beans programming model. Using JPA a Java developer can persist data for the desktop application as well as web application. JPA uses annotations so it requires the JDK 1.5 or higher version of Java.

Architecture Of JPA

JPA was introduced to simplify the EJB entity beans programming model. JPA persists the Java objects to the relational database using metadata. It maps the Java objects to the relational database table. Like SQL JPA has has the support of a query language to execute queries. It can execute both static and dynamic queries. JPA can be used with the various ORM frameworks like, Hibernate, Toplink from Oracle, iBatis, etc.

Features Of JPA

JPA has the various features that attracts developers to use persist data in the database table. Some of these features are as  :

  • JPA can be used with the third party persistence providers like, Hibernate, Toplink etc.
  • It has the support of annotation that prevent developers to write extra line of codes.
  • JPA capabilities can be used with the desktop applications also.
  • JPA can execute both static and dynamic queries.
  • No need to use more Java classes for developing persistence applications.

JPA Entities

Persistence entity is a Java class whose state has to be persisted into a relation database table. Each row of this table is constituted as the instance of the entity class. There can be a relationship between entities and they can be expressed through object/relational metadata. This metadata can be defined either directly using annotations inside the entity class or by creating a XML file.

Entity inheritance JPA

Entity inheritance in JPA specifies the entities inheritance. An entity class can inherit non-entity classes and the non-entity classes can inherit entity.

How To Manage Entities In JPA ?

javax.persistence.EntityManager manages the Entities in JPA. Finds the entities in the data store using find() method of EntityManager with their primary key. Manage the life cycle of entity instances. Persist the entity instance.

JPA Querying Entities

There are various methods provided by JPA for querying entities. Java Persistence Query Language provides the simple query language like SQL. Java Persistence Criteria API provides to create typesafe queries.

For reading more about JPA please go through the link http://www.roseindia.net/jpa/index.shtml.

For JPA example click here http://roseindia.net/jpa/jpa-examples.shtml.

Tutorials

  1. JPA getResultList Example
  2. JPA Native Queries, JPA Native Queries Tutorials
  3. JPA Sub-Queries
  4. JPA Named Query
  5. JPA One-to-Many Relationship
  6. JPA setParameter (Numbered Parameter)
  7. JPA Many-to-Many Relationship
  8. JPA Max Function
  9. JPA Avg Function
  10. JPA-QL Queries
  11. JPA One-to-One Relationship
  12. JPA Named Parameter
  13. JPA Positional Parameter
  14. JPA Ordering
  15. JPA Grouping
  16. JPA Sum Function
  17. JPA Min Function
  18. JPA Substring() Function
  19. JPA Trim() Function
  20. JPA Lower() Function
  21. JPA Upper Function
  22. JPA Length Function
  23. JPA Locate Function
  24. JPA Mod Function
  25. JDBC vs ORM
  26. JPA Introduction
  27. JPA Architecture
  28. JPA Tutorials
  29. JPA Examples In Eclipse
  30. JPA getSingleResult
  31. JPA update data Example
  32. JPA Features
  33. JPA setFirstResult Example
  34. JPA delete data
  35. JPA executeUpdate
  36. JPA Relationship
  37. JPA Count Function
  38. JPA Examples in NetBeans
  39. JPA Crud
  40. Developing JPA CURD Application with Eclipse