Hello all, I’m hoping for some assistance in figuring out how to implement a fairly complex mapping problem. Here is what I have to deal with in a legacy database situation (that I can't change - I have to adapt the mapping to):

1. Our current purchase order information is stored on a table called ‘PURCHASE_ORDER’.
2. Our older purchase order information is stored in an identical (structure-wise) table called ‘PURCHASE_ORDER_HIST’.
3. The primary key to these tables is PO_NUMBER and PO_SEQUENCE.
4. A given PO_NUMBER and PO_SEQUENCE will exist on either PURCHASE_ORDER or PURCHASE_ORDER_HIST, but not both.
5. The legacy applications that need to retrieve information for a given PO_NUMBER and PO_SEQUENCE have to query both tables to locate the information.

I have an entity class called PurchaseOrder which I need to somehow map to BOTH tables and have the persistence layer automagically load the data. So far, I have only mapped this entity to the PURCHASE_ORDER table, and now need to figure out some way to also map it to PURCHASE_ORDER_HIST.

Basically, the persistence manager needs to query PURCHASE_ORDER, and if it doesn't find it there, query PURCHASE_ORDER_HIST. I'm currently just figuring out how to get it to load the correct entity; eventually, I'm going to have to try to figure out how get the persistence layer to update the correct table if an entity is changed.

Is this a scenario where some sort of Inheritance mapping could help?

Thanks for any help.

Hi,

maybe you can utilize the Custom SQL for CRUD operations feature - http://www.hibernate.org/hib_docs/annotations/reference/en/html_single/#entity-hibspec-customsql.

--Hardy