Changing the type of an entity preserving its ID

Question

I am using hibernate as a persistence layer. There are 2 entities that live in the same table extending one superclass with single table inheritance strategy.

Answer 1

You can use your own id (not generated) and do the following:

1. Retrive B
2. open transaction
3. delete B
4. commit the transaction
5. open a new transaction
6. create C and persist it
7. Close the second transaction

In this way you will clear the id from the table before re-inserting it as C.