Hi, maybe someone can give me a little jumpstart on the following problem:

What i want to do is to build a base class with a set of fields and methods, that will be used in 3 subclasses. I try to describe the layout as best I can.

Base Class Contact Contains Tables
ContactID
Addresses
Phones
Faxes
Bank Info
CreditCard Info

Subclass CustomerContact extends Contact and contains additional Tables
CustomerAccount
Personal Info

Subclass BusinessContact extends Contact and contains additional Tables
BusinessAccount
Business Info

Subclass ClientContact extends Contact and contains additional Tables
ClientAccount
Business Info

How can I map this Construct using annotations or xml? I run into the following problems:
Though Hibernate is able to map inherited classes, it needs an identifier in the record of its base table (in this case contactid) to identify the class that this record belongs to. However the same ContactID Record can belong to all 3 subclasses and distuinguishes only by the existence of the tables CustomerAccount, BusinessAccount and ClientAccount which Type i will actually use. Obviously I can model all 3 Objects to be independent from each other and i will be able to map them properly. But this is ugly and not good code. If possible I would like to use the approach via inheritance. Any Comments greatly appreciated.

Regards
Andreas

With "Table per class hierarchy" inheritence mapping the discriminator in the base class mapping is something hibernate manages. It doesn't need to appear in your object at all, you never set it or read it. Hibernate simply uses it to determine which kind of object a particular row represents.

Here's a basic outline:

Thanks for the very fast response.

This is the general info i found on the subject. However my Problem is, that I cannot (want not) set a column contact_type in table contact. The Entity Diagram reads:

Contact 1 to n BusinessAccount
Contact 1 to n CustomerAccount
Contact 1 to n ClientAccount

meaning 1 contact can have all 3 Attributes e.g. be a Client, be a Customer, be a BusinessPartner.

Regards
Andreas

Add:
I might make a general Design mistake here. Maybe Contact is not the Base Class of BusinessContact/ CustomerContact/ ClientContact... but I havent found a better way to model their Relations.

Regards
Andreas

If a Contact can have all the account types then its not a hierarchy, simply a group of one-to-many properties on the Contact class.