Inheritance in mapping workbench

Question

I try to use an existing class design with TopLink: I have for each table classes for value objects (*VO) containing only the attributes from the database tables (including the foreign keys). And I have classes for composite objects (*CO) inherited from *VO, additional containing the references to other VO and CO objects.
A simple example:
class FirstVO           // attributes for first database table
private long id;     // database primary key
private long secondId;// database foreign key to second table
class FirstCO extends FirstVO      // references from first database table
private SecondVO second;     // object reference to second table's object
class SecondVO           // attributes for second database table
private long id;     // database primary key
In TopLink mapping workbench I have done the mapping for classes *VO. That's okay.
When I try to do the mapping for class FirstCO, I get problems:
- TopLink mapping workbench recognizes the class hierarchy for FirstCO fine and displays it in class info.
- But there is not way in workbench to do the mapping of the inherited attributes for class FirstCO.
- It does not recognize that it could use the mapping from inherited class FirstVO also for FirstCO. Setting in Descriptor/...FirstClassCO.ClassDescriptor.xml the attribute Descriptor/mappings/Mapping/inherited to true will not change this (but a green arrow up is displayed with FirstCO).
- The workbench displays an error about class FirstCO: The following primary key fields are unmapped: ID
How can I map this field?

Answer 1

Have you setup the descriptor inheritance? Right click on the Descriptor's FirstVO and FirstCO, and select "Advanced properties--inheritance". Set the Parent Decriptor for FirstCO to be FirstVO (it's on the bottom of the inheritance tab). When you do that, you should be able to map the inherited attributes with no problems. Basically, you can remap (aka override" the mappings for superclass in subclasses.
- Don