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Hibernate version: 3.2

I need to store complex objects (objects with child records), but also store potential revisions (awaiting approval) to these objects, and am not sure how I should handle my outrigger tables or mapping strategy.

Imagine I have an entity representing the current set of a customer profile:

Customer (
customerId,
firstname
lastname,
phone
...
...several dozen other flat fields...
...
)

CUSTOMER also has, for example, a many-to-one outrigger table of CUSTOMER PETS.

CUSTOMER_PET (
customerPetId,
customerId,
pet_name
pet_type
pet_age)

Finally, and here is the real problem, I need to manage the idea of an entity called CUSTOMER_UPDATE,
which contains all fields (and child records) for a customer object, plus a date submitted, a submitted_by, and some bookkeeping information.

This includes changes to the CUSTOMER_PET outrigger table.

My question is how to appropriately model this from an ER standpoint:

Solution 1:
I can manage two separate tables, CUSTOMER and CUSTOMER_UPDATE, with separate CUSTOMER_PET and CUSTOMER_UPDATE_PET child tables. On a hibernate level, though, this is a bit messy. From what I know of hibernate, I got the feeling that I would be mapping almost-identical objects to almost-identical tables. I didn't know if there were some tricks that would allow me to reuse the mapping for customer in a customer_update object, or the mapping for CUSTOMER_PET in a CUSTOMER_UPDATE_PET object.

Solution 2:
I can make a
CUSTOMER_ABSTRACT table:

CUSTOMER_ABSTRACT(
customer_abstract_id PK,
firstname
lastname,
phone
...etc....)

and two joined subclass tables for CUSTOMER and CUSTOMER_UPDATE.

CUSTOMER(
CUSTOMER_ID,
customer_abstract_id FK, unique),
)

CUSTOMER_UPDATE(
CUSTOMER_UPDATE_ID,
customer_abstract_id FK, unique),
date_submitted,
submitted_by,
other_bookkeeping_columns
)

This would allow me to get by with only one CUSTOMER_ABSTRACT_PET outrigger, by keeping a foreign key to CUSTOMER_ABSTRACT as opposed to CUSTOMER.

CUSTOMER_UPDATE(
CUSTOMER_UPDATE_ID,
customer_abstract_id FK, unique),
date_submitted,
submitted_by,
other_bookkeeping_columns
)

I think I know how to map this, using joined subclasses.

If anyone knows any other ways of approaching the update-approval problem, I would like to hear them.

In short, I am looking for best practices for persisting object graphs and the proposed changes to said graphs.

Many thanks,
JFD

I think joined subclasses seems like a perfect solution.

John.