Bug 277333

Summary:	Example of using custom query keys for casting of relationships into inheritance hierarchy
Product:	z_Archived	Reporter:	Doug Clarke <douglas.clarke>
Component:	Eclipselink	Assignee:	Nobody - feel free to take it <nobody>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	normal
Priority:	P3	CC:	fs5, matthias.bross
Version:	unspecified	Keywords:	example
Target Milestone:	---
Hardware:	All
OS:	All
URL:	http://wiki.eclipse.org/EclipseLink/JPA/CastingUsingQueryKey
Whiteboard:	under development and review

Description Doug Clarke

2009-05-21 10:35:36 EDT

This example will use custom relationship query keys to show how queries can be built that reference into an inheritance hierarchy below the root and thus provide access to additional mapped values of the subclasses. This example is based on the User Guide's documentation on how to add custom query keys in Java code:

http://wiki.eclipse.org/Configuring_a_Descriptor_(ELUG)#How_to_Configure_Query_Keys_Using_Java

Comment 1 Doug Clarke

2009-05-21 11:55:51 EDT

Initial version of example checked in @ /svnroot/rt/org.eclipse.persistence/branches/1.1.0/trunk/examples/org.eclipse.persistence.example.jpa.cast

Comment 2 Doug Clarke

2009-05-21 11:59:10 EDT

The interesting part of this example is the CastQueryKeyFactory that creates the custom query keys based on an existing mapping and a new target subclass.

http://dev.eclipse.org/svnroot/rt/org.eclipse.persistence/branches/1.1.0/trunk/examples/org.eclipse.persistence.example.jpa.cast/src/utils/CastQueryKeyFactory.java

In this example a custom query key is created called 'oneToOneA' and is then used in a simple query:

        CastQueryKeyFactory.addCastQueryKey(getEMF(), Source.class, "oneToOne", InhChildA.class, "oneToOneA");

        EntityManager em = getEntityManager();

        ReadAllQuery raq = new ReadAllQuery(Source.class);
        ExpressionBuilder eb = raq.getExpressionBuilder();
        raq.setSelectionCriteria(eb.get("oneToOneA").get("aValue").like("a%"));
        raq.setShouldOuterJoinSubclasses(true);
        raq.addAscendingOrdering("id");

        List<Source> sources = JpaHelper.createQuery(raq, em).getResultList();

Comment 3 Doug Clarke

2010-06-06 08:56:28 EDT

Given the new support for both casting (TREAT AS) in JPQL as well as support for using query keys in JPQL I am going to change the wiki to indicate that the examples shown were for versions before 2.1. No additional work on this example will be performed.

Comment 4 Eclipse Webmaster

2022-06-09 10:16:58 EDT

The Eclipselink project has moved to Github: https://github.com/eclipse-ee4j/eclipselink

Comment 5 Eclipse Webmaster

2022-06-09 10:29:21 EDT

The Eclipselink project has moved to Github: https://github.com/eclipse-ee4j/eclipselink