Problem: cannot implement TABLE_PER_CLASS inheritance

Question

Hello, I'm using Jdev 11g, JPA (with EclipseLink 1.1.1) & EJB 3.0. I'm trying to build TABLE_PER_CLASS inheritance.
Here is entities' code:
Parent:@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
@NamedQueries( { @NamedQuery(name = "Doc.findDoc",
query = "select o from Doc o where o.docDate between :begDate and :endDate")
public abstract class Doc implements Serializable {
@Id
@Column(name = "ID")
private Long id;
@Column(name = "DOC_NUMBER")
private String docNum;
@Column(name = "DOC_DATE")
@Temporal(TemporalType.TIMESTAMP)
private Date docDate;
public Doc() {
super();
Child:@Entity
@Table(name = "PAY_DOC")
public class PayDoc extends Doc implements Serializable{
@Column(name = "SUM")
private BigDecimal sumOfMoney;
public PayDoc() {
super();
persistence.xml looks like this:<?xml version="1.0" encoding="UTF-8" ?>
<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"
version="1.0" xmlns="http://java.sun.com/xml/ns/persistence">
<persistence-unit name="context">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<jta-data-source>java:/app/jdbc/jdbc/inform_oracam00DS</jta-data-source>
<class>Doc</class>
<class>PayDoc</class>
<properties>
<property name="eclipselink.target-server" value="WebLogic_10"/>
<property name="eclipselink.target-database" value="Oracle10g"/>
<property name="javax.persistence.jtaDataSource"
value="java:/app/jdbc/jdbc/inform_oracam00DS"/>
</properties>
</persistence-unit>
</persistence>
When I'm trying to call method, which calls Doc.findDoc query:
public List<Doc> queryDoc() {
Date begDate = new GregorianCalendar(2007, 10, 1).getTime();
Date endDate = new Date();
return em.createNamedQuery("Doc.findDoc").setParameter("begDate",
begDate,
TemporalType.TIMESTAMP).setParameter("endDate",
endDate,
TemporalType.TIMESTAMP).getResultList();
I get no table found SQL error and JPA is trying to execute query like
SELECT FROM DOC WHERE ...
Looks like EclipseLink sets wrong table name.
P.S. When I added second child, the query was the same and there was no union in it.
Edited by: tag on 26.08.2009 21:27

Answer 1

Hello,
As Anindita mentioned, this query will force reading from all the tables in the inheritance heirarchy, including the DOC table. Since it does not exist, you get the exception. I do not believe that any JPA provider could work in this senario, since the specification requires providers to query on Doc since it is marked as an Entity, even though you have marked it as an abstract class
I believe you might get past this problem if you mark the Doc class as a @MappedSuperClass instead of an entity. This will cause it to be correctly interpreted as not being instantiated, and so will not require a DOC table be defined.
Best Regards,
Chris