Inheritance based on USER column and JPQL based on @ManyToOne column

Question

I wanted to build a simple inheritence scheme for no other reason than to support a generalized table that I could manipulate in standard libraries and to extend that table with columns that might exist in various customer implementations. In the extra-ordinarily simple example that follows I created a base Parcel class; extend that with a ParcelBean which has a column specific to a user; and extend that further with a wrapper class that will include some Trinidad references that I want to keep completely away from the bean classes. In short, I wanted to put together an inheritence scheme for basic OO reasons, not because of any particular table structure.
After some thought I figured that the best way to do this might be to use the Single-Table Strategy, especially after I discovered that I could fool the system by using the Oracle USER pseudo-column for my DiscriminatorColumn and use my schema name for the DiscriminatorValue.
@Entity
@Table(name = "PARCEL")
@Inheritance
@DiscriminatorColumn(name = "USER")
public class Parcel {
  String parcelPin;
  public Parcel() {
  @Id
  @Column(name = "PARCELPIN", nullable = false)
  public String getParcelPin() {
    return parcelPin;
  public void setParcelPin(String parcelPin) {
    this.parcelPin = parcelPin;
@Entity
public class ParcelBean extends Parcel {
  LandUseType luc;
  public ParcelBean() {
  public void setLuc(LandUseType newluc) {
    this.luc = newluc;
  @ManyToOne
  @JoinColumn(name = "LUC")
  public LandUseType getLuc() {
    return luc;
@Entity
@DiscriminatorValue("CPC")
public class ParcelRow extends ParcelBean {
  public ParcelRow() {
  public void doSomething(ActionEvent ae) {
    ; // Trinidad code
}For a couple of weeks this has been working fine. Right up until I tried to a JPQL like the following:
"select p from ParcelRow p where p.luc.cpcCode=12"The problem is that TOPLINK will generate SQL that prefixes USER with an alias (something it does not do if there isn't a foreign key reference involved). This won't work because Oracle SQL does not allow aliases on pseudo-columns
select USER from PARCEL; -- return CPC
select p.USER from PARCEL p; -- throws ORA-01747: invalid user.table.column specificationSo now I'm in a jam. I can't (read won't if you will) give up on my requirement for inheritence. I have multiple clients with the same basic legacy table with minor variations and I have tens of thousands of lines of code that work on the basic core table properties and I don't want to copy and paste. I could use interfaces, except that I would still have to extend the Beans with my Row classes so that I could add the JSF actionListeners (and other such stuff). I need to be able to select Lists of these Row classes with the JSF methods so that I can expose them as values to JSF/Trinidad/ADF Tables and it break every person pattern I enforce to mix JSF and JPA dependencies in the same class.
Anyone out there have any ideas?
Thanks Mark

Answer 1

Of course a simple fix for this problem would be if the Oracle provider code was smart enough to recognize pseudo columns and to not prefix them with an alias.
Is there any chance that this might be done before a final release?
Mark