JPA discriminator column problem

Hallo all. I have this set of classes:

@Entity
@Table(name = "S_MC_CC_RAPPORTI")
@Inheritance(strategy=InheritanceType.JOINED)
@DiscriminatorColumn(name="COD_TIPORAPPORTO",
                     discriminatorType=DiscriminatorType.CHAR, length=1)
public abstract class Rapporto implements Serializable {

  private static final long serialVersionUID = -5567166522882040440L;
 
  @Id
  @Column(name = "COD_RAPPORTO")  
  protected Long codiceRapporto;

And this sublass:

@Entity
@Table(name="S_MC_CC_CCCLIENTI")
@DiscriminatorValue("1 ")
public class ContoCorrente extends Rapporto {
  private static final long serialVersionUID = -3380622649760983262L;

  @Column(name = "DESC_DIVISA")
  private String divisa;

The problem is on the discriminator value: on the table the column is CHAR(2).

When I make the getItemById on the subclass all works fine: this is the generated eclipselink sql: (I replaced the column definition with * for easy to read)

[EL Fine]: 2011-01-16 16:01:14.531--ServerSession(5230193)--Connection(11601738)--Thread(Thread[main,5,main])--  SELECT * FROM S_MC_CC_RAPPORTI t0, S_MC_CC_CCCLIENTI t1 WHERE ((t0.COD_RAPPORTO = ?) AND ((t1.COD_RAPPORTO = t0.COD_RAPPORTO) AND (t0.COD_TIPORAPPORTO = ?)))
 bind => [1120676, 1 ]

If I change the @DiscriminatorValue("1") removing the space the data is not found: this is the relative generated sql

开发者_Python百科[EL Fine]: 2011-01-16 16:03:46.671--ServerSession(5230193)--Connection(11601738)--Thread(Thread[main,5,main])--SELECT * FROM S_MC_CC_RAPPORTI t0, S_MC_CC_CCCLIENTI t1 WHERE ((t0.COD_RAPPORTO = ?) AND ((t1.COD_RAPPORTO = t0.COD_RAPPORTO) AND (t0.COD_TIPORAPPORTO = ?)))
 bind => [1120676, 1]

Note that the two queries work fine with TOAD: both the t0.COD_TIPORAPPORTO = '1 ' one, even the t0.COD_TIPORAPPORTO = '1'.

OK: so I think that the @DiscriminatorValue("1 ") is correct.

Now I make an association many-to-many with the super class Rapporto as described here

If I mantain the @DiscriminatorValue("1 ") I get

[EL Warning]: 2011-01-16 16:09:33.421--ServerSession(29839159)--Thread(Thread[main,5,main])--Exception [EclipseLink-43] (Eclipse Persistence Services - 2.1.2.v20101206-r8635): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Missing class for indicator field value [1] of type [class java.lang.String].
Descriptor: RelationalDescriptor(it.alten.intesasanpaolo.contratto.domain.core.rapporto.Rapporto --> [DatabaseTable(S_MC_CC_RAPPORTI)])

If I change the @DiscriminatorValue("1") removing the space all work fine but I receive no data (even If the data is present on DB).

I dunno what to do.... Any idea?

Kind regards

Massimo

Your database seems to have an issue with char comparison with spaces when using binding. What database are you using?

There are several possible solutions, first I would check with your JDBC driver to see if it has any fixes or options to solve this.

One option is to set "eclipselink.jdbc.bind-parameters"="false" in your persistence.xml, this should resolve the issue.

Another solution is to disable char trimming in EclipseLink, (this one does not seem to be exposed to JPA persistence properties (please log a bug), so you need to use a SessionCustomizer to set it) session.getLogin().setShouldTrimStrings(false);

A more involved solution is to use a DescriptorCustomizer to set your own ClassExtractor on the descriptor to use you own code to determine the class.

If you can change the data, then I would recommend just updating any '1 ' to '01' then you can just use '01' as the indicator.

It appears that the values in your database contain a trailing space. I'd suggest to run a query against the table and remove the trailing whitespace. Then have the discriminator value be "1" (no space)

In fact, if you are going to use numbers anyway, you should use DiscriminatorType.INTEGER