Aggregate inheritence

Question

Is there some documentation or tutorial I can find for doing inheritence using Aggregates? I have seen in http://download.oracle.com/docs/cd/B32110_01/web.1013/b28218/descun.htm it states "When configuring inheritance for a relational aggregate descriptor, all the descriptors in the inheritance tree must be aggregates. The descriptors for aggregate and non-aggregate classes cannot exist in the same inheritance tree." So I am guessing it can be done, but I do not see how to do it anywhere.

Answer 1

Thank you so much. For those that may need this in the future, I will give a full solution to this. In the inherited aggregates, map the fields as they would normally be mapped. So, in this case, inside the Toplink Workbench, I would map extension as direct-to-field.
Then, inside the class that holds the aggregate, you need to add an "After Load" method.
public void afterLoadPerson(ClassDescriptor descriptor) {
AggregateObjectMapping mapping = (AggregateObjectMapping )aDesc.getMappingForAttributeName("phoneNum");
mapping.addFieldNameTranslation("XE.PERSON.EXTENSION", "extension->DIRECT");
}This way, the direct-to-field mapping of the extension attribute in NumberAndExtension will be mapped to the database field it should be mapping to for the Person class.
Then, if some other class and table need to use the Number aggregate with inheritance, the same method would be followed, except instead of doing "XE.PERSON.EXTENSION", the other table and field name would be place here.