I interface with two data stores, one of them is RDMS and the other one is LDAP. What I want to do is to have a hierarchy persisted using "superclass-table" in the RDBMS and "complete-table" in LDAP.
Is such a thing possible? That is, can you specify multiple inheritance strategies, separately for each data store in the *.orm files or am I forced to use a single inheritance strategy?
I couldn't find this information in the documentation of DataNucleus, they only thing I'm sure of is that you can put inheritance elements in an .orm file instead of the .jdo but that still doesn't answer my question...
The hierarchy is rather simple and consists of an abstract class and several subclasses like this:
abstract class Foo implements IFoo
{
...
}
class Foo1 extends Foo
{
...
}
class Foo2 extends Foo
{
...
}
...
I tried to configure inheritance in the two *.orm files AND in the .jdo file (having in mind that it's going to get overriden by the former) but I get an exception
Caused by: org.datanucleus.metadata.InvalidMetaDataException: Class "...Foo1..." has been specified with an inheritance strategy of "superclass-table", yet no superclass exists or none exists with its own table!
at org.datanucleus.metadata.AbstractClassMetaData.validateUserInputForInheritanceMetaData(AbstractClassMetaData.java:903)
at org.datanucleus.metadata.ClassMetaData.populate(ClassMetaData.java:214)
at org.datanucleus.metadata.MetaDataManager$1.run(MetaDataManager.java:2393)
at java.security.AccessController.doPrivileged(Native Method)
at org.datanucleus.metadata.MetaDataManager.populateAbstractClassMetaData(MetaDataManager.java:2387)
at org.datanucleus.metadata.MetaDataManager.populateFileMetaData(MetaDataManager.java:2224)
at org.datanucleus.jdo.metadata.JDOMetaDataManager.loadMetaDataForClass(JDOMetaDataManager.java:741)
at org.datanucleus.jdo.metadata.JDOMetaDataManager.getMetaDataForClassInternal(JDOMetaDataManager.java:353)
at org.datanucleus.jdo.metadata.JDOMetaDataManager$MetaDataRegisterClassListener.registerClass(JDOMetaDataManager.java:184)
at javax.jdo.spi.JDOImplHelper.registerClass(JDOImplHelper.java:376)
I then tried to remove the inheritance elements from the .jdo but the enhancer fails with the following message:
Class "...Foo1..." has been specified to use an inheritance strategy of "superclass-table", persisting to the table of class ...Foo..., however this class doesnt have a discriminator specified.
The individual configurations are correct (new-table with discriminator at base-class and superclass-table at subclasses for the first case and complete-table only at base-class for the second).
