Hello,

I'm using JPA w/Hibernate. I have a User entity and multiple subclass entities like Customer, Admin, etc. I need the ability to convert from a Customer to an Admin. The way I've tried to do this is create a new Admin instance, copy all properties over including the Id of the Customer, delete the Customer entity and persist the Admin.

With a little tweaking (using getReference() before the remove and flush() after the remove) I have it all working fine.

The problem, however, is that the new entity I am saving has a newly generated Id. I need it to have the Id of the entity I just deleted so that many foreign key references remain valid.

The behavior I think I'm looking for is something like: if id=null, generate as normal. Otherwise use the Id that's been set.

Ideas?

I dont think there is a straight forward way to do this. Plz see:
http://forum.hibernate.org/viewtopic.ph ... 2b04766891

But I could think of a solution. I am assuming that you are using Table per class hierarchy mapping. What you can do is map the same table to another POJO which will include all the fields of User, Customer and Admin and the discriminator field. Now use this entity to update the discriminator field to convert your Customer to Admin.

I would also do something similar to littypreethkr's solution: create a native sql query where you update the discriminator column.