[jboss-user] [EJB 3.0] - Inheritence and EJBQL

tynor do-not-reply at jboss.com
Sat Sep 22 13:57:06 EDT 2007

Can EJBQL be used to query polymorphically?  I cannot find any examples in the spec or in Bill Burke's EJB3 book, and my attempts are always returning null.

l = entityManager.createQuery("SELECT s FROM Security s").getResultList();

Here I'm trying to find all rows of all security subclasses.  Even though the database has many such entries, the query always returns null. I can find each subclass independently - eg.: 
l = entityManager.createQuery("SELECT s FROM SecurityLoan s").getResultList();
  | l = entityManager.createQuery("SELECT s FROM SecurityEquity s").getResultList();

but would like to write a single query to get all objects, regardless of subclass. 

My entities are declared using JOINED inheritence:

  | @Entity
  | @Table(name = "security")
  | @Inheritance(strategy = InheritanceType.JOINED)
  | public class Security implements java.io.Serializable {
  | ....
  | @Entity
  | @Table(name = "security_loan")
  | @PrimaryKeyJoinColumn(name="security_id")
  | public class SecurityLoan extends Security implements java.io.Serializable {
  | ....
  | @Entity
  | @Table(name = "security_equity")
  | @PrimaryKeyJoinColumn(name="security_id")
  | public class SecurityEquity extends Security implements java.io.Serializable {

Is this possible? 

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