InheritanceType JOINED stategy problem

[grdzeli_kaci]

hi all,
i have 3 table into database
Root Table : PAYMENT_METHOD_DATA
Child Table : BANK_TRNSF_METHOD_INFO
Child Table : SCRATCH_METHOD_INFO

in java i have inheritance joined strategy, then root class loojks like this :

@Entity()
@Table(name = "PAYMENT_METHOD_DATA", schema = "CCARE")
@Inheritance(strategy = InheritanceType.JOINED)
@DiscriminatorColumn(name = "METHOD_DATA_TYPE", discriminatorType = DiscriminatorType.STRING)
@DiscriminatorValue("Base_MethodData")
public abstract class PaymentMethodData implements Serializable {
}

then fiers child looks like :

@Entity()
@Table(name = "BANK_TRNSF_METHOD_INFO", schema = "CCARE")
@DiscriminatorValue("BankTransfer_MethodData")
public class BankTrnsfMethodInfo extends PaymentMethodData implements
 Serializable {
}

second child :

@Entity()
@Table(name = "SCRATCH_METHOD_INFO", schema = "CCARE")
@DiscriminatorValue("Scratch_methodData")
public class ScratchMethodInfo extends PaymentMethodData implements
 Serializable {
}

when i persist BankTrnsfMethodInfo entity object,
automatically persisted also PaymentMethodData, but into PAYMENT_METHOD_DATA column METHOD_DATA_TYPE value is NULL. i don't understand what heppened

can anybody help me ?

Regards,
Paata.

[rajeshv7]

I think you have mixed up the 'SINGLE_TABLE' and 'JOINED' Inheritance strategies. The Discriminator's are specified only in the 'SINGLE_TABLE' strategy. And in the 'Joined' since all the subclasses have their own tables there is no need for a discriminator column.

[grdzeli_kaci]

"rajeshv7" wrote:
I think you have mixed up the 'SINGLE_TABLE' and 'JOINED' Inheritance strategies. The Discriminator's are specified only in the 'SINGLE_TABLE' strategy. And in the 'Joined' since all the subclasses have their own tables there is no need for a discriminator column.

you are not right!

The Discriminator's are not specified only in the 'SINGLE_TABLE' strategy. it is possible to use into join strategy.

i have book "Pro EJB3 Java Persistence API" (Mike Keith and Merrick Schincariol)
http://www.amazon.com/Pro-EJB-Java-Persistence-API/dp/1590596455

on page 249 is defined joined strategy and tehere is data model in example Employee, FullTimeEmployee,PartTimeEmployee and ContractEmployee using Joined Strategy.


find out here Example 1-74
http://www.oracle.com/technology/products/ias/toplink/jpa/resources/toplink-jpa-annotations.html


Is There any idea ?

I can't resolve this problem

[grdzeli_kaci]

is anybody use this strategy ?
i can't resolve this problem yet :(

[grdzeli_kaci]

i can't resolve this problem yet, could anybody help me ?

[grdzeli_kaci]

anybody knows where is documentations about it ?