Tag Archives: Database

JPA: Implementando la persistencia con EclipseLink

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Veamos como implementar la persistencia en un proyecto de Eclipse con el estándar JPA implementado por EclipseLink.

Nos basaremos en el proyecto de Eclipse creado en el artículo anterior.  En las propiedades (botón derecho) del proyecto añadimos el “poder” de manejar Entidades JPA, añadiendo el Facet:

Adding JPA facet

Utilizaremos EclipseLink 1.1.2 ya que es la implementación de JPA por defecto en WebLogic 11g.

Generar Entidades desde las tablas

Sobre el proyecto en el menu contextual (botón derecho), JPA > Generate Entities from Tables… Elegimos la conexión SCHOOL creada anteriormente, y las tablas REGISTRY y SCHOOLCERTIFICATES. Generando las entidades en el paquete lebrijo.school.model:

Generating entities from tables

Para mantener la coherencia de JPA debemos añadir un Identificador a todas las clases, Registry lo tiene, pero a SchoolCertificates hay que añadírselo:

Add Identifier

Es muy interesante observar el fichero src/META-INF/persistence.xml, como se configura la conexión y se mapean las entidades.

<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="school" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
 	<class>lebrijo.school.model.Registry</class>
 
 	<class>lebrijo.school.model.Schoolcertificate</class>
		<properties>
			<property name="eclipselink.target-server" value="WebLogic_10"/>
			<property name="eclipselink.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
			<property name="eclipselink.jdbc.url" value="jdbc:oracle:thin:@192.168.0.7:1521:xe"/>
			<property name="eclipselink.jdbc.user" value="school"/>
			<property name="eclipselink.jdbc.password" value="school"/>
			<property name="eclipselink.logging.level" value="FINEST"/>
		</properties>
 </persistence-unit>
</persistence>

Aquí os dejo el zip del proyecto eclipse tras estas modificaciones.

JPA: persistence with EclipseLink

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Today we will see how to make the persistence in a Eclipse project with EclipseLink JPA implementation.

We will base in the last post Eclipse project. In the project properties (right buton) we will add the power to manage JPA entities, adding the facet:

Adding JPA facet

We will ue EclipseLink 1.1.2, it is the JPA implementation by defect in WebLogic 11g.

Generating entities from tables

Over the project, in the contextual menu (right button), JPA > Generate Entities from Tables… We choose the conection SCHOOL, created in other posts, and tables REGISTRY and SCHOOLCERTIFICATES. Generating the entities in the package lebrijo.school.model:

Generating entities from tables

To maintain the JPA coherence we must add an Identifier on every classes, Registry has one, but we must add one to SchoolCertificates:

Add Identifier

You may see the file src/META-INF/persistence.xml, how it configures the connection and map the entities.

<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemalocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
<persistence-unit name="school" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
 	<class>lebrijo.school.model.Registry</class>
 
 	<class>lebrijo.school.model.Schoolcertificate</class>
		<properties>
			<property name="eclipselink.target-server" value="WebLogic_10"/>
			<property name="eclipselink.jdbc.driver" value="oracle.jdbc.OracleDriver"/>
			<property name="eclipselink.jdbc.url" value="jdbc:oracle:thin:@192.168.0.7:1521:xe"/>
			<property name="eclipselink.jdbc.user" value="school"/>
			<property name="eclipselink.jdbc.password" value="school"/>
			<property name="eclipselink.logging.level" value="FINEST"/>
		</properties>
 </persistence-unit>
</persistence>

here I leaveth eclipse zip project after these steps.

Data Model Design with JDeveloper

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I consider JDeveloper as a great data base design tool for some reasons:

  • It can navigates through the Oracle databases
  • It has a very good ER editor.
  • It can change the data base schema when you modify the diagram

We can download from Oracle’s web the last JDeveloper version for our operating system. Installing is very easy, you just must have installed the JDK.

Continue reading Data Model Design with JDeveloper →