Generators do not rollback

[Carlos Otero Barros]

Hi all;

Generators used inside a transaction do not rollback when the transaction
does rollback. This is the logical consequence for generators being a common
resource for all the active transactions.
Now, the problem with this behavior is that you cannot rely generators for
fields that should have sequential values in each row. For example, supose
you have high concurrency on a ORDERS table and supose you do not want
unused order numbers but sequential ones. How do you manage this situation?

Thank you.