[hibernate-issues] [Hibernate-JIRA] Commented: (HHH-3642) EJB3 inheritance strategy TABLE_PER_CLASS does not work on HSQLDB

EJB3 inheritance strategy TABLE_PER_CLASS does not work on HSQLDB ----------------------------------------------------------------- Key: HHH-3642 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-3642 Project: Hibernate Core Issue Type: Bug Affects Versions: 3.3.1 Environment: JBoss 5.0GA, Java 1.6, Hypersonic 1.8.0.8 Reporter: Wolfgang Knauf Attachments: InheritanceTablePerClass.ear I use an EJB3 entity bean with inheritance strategy "TABLE_PER_CLASS": @Entity @Inheritance(strategy=InheritanceType.TABLE_PER_CLASS) public abstract class Base implements Serializable { ... When loading a list of base classes, all subclass fields are null. The union subclause in the query does not work on HSQLDB. Attached is a full EJB sample, runnable on JBoss 4.2/5.0 (project export of Eclipse 3.4/WebTools 3.0 with sources). After deploying, it can be tested by browsing to http://localhost:8080/InheritanceTablePerClassWeb/ See this output: ... Loading ALL Item: Child 1, child field 1: null Item: Child 2, child field 2: null Item: Child 3, child field 3: Field of Child3 ... Here, all childs are loaded. The fields of type "Child1" and "Child2" are null, fields of type "Child3" are filled. This is probably a duplicate of http://opensource.atlassian.com/projects/hibernate/browse/HHH-2920 The described workaround to change all NULL expressions to "cast (null as VARCHAR)" results in a working query, but I see no chance to pre-configure this query in the entity manager. I created another bug, because the impact is different (it breaks a feature of EJB3), and so I consider severity to be higher.