Solution for rolling back many transactions?

[Phillip Tornroth <ptornroth@xxxxxxxxxxxxxx>]

The most cumbersome part of our many (hundreds) of unit tests that  
verify our data access is working, is creating and then deleting all  
of the test data. Currently, we're doing it at a pretty high level  
using java and our ORM (hibernate). It occurred to me that I can  
probably speed the deletion up by implementing a stored procedure to  
help do the cleanup. This way we don't pay the penalty for a lot of  
object construction and individually-issued delete statements.. This  
might help, but half way through writing it I wondered if there's an  
even easier solution...

What I want is to be able to roll the state of the database back to  
the way it was when the test began. Essentially, I want the same  
behavior I'd get if I backed the database up and then re-imported it  
afterward.. Only I need the process to add very little overhead (less  
than a second).

Are there any creative ways to accomplish this? I figured I'd ask the  
list before trudging forward with my still-not-optimal stored procedure.

In case it's useful information, the test database is pretty small...  
Maybe 15 or 20 megs. The unit tests are individually pretty small..  
Less than 100 inserts each, for sure... So there's not that much to  
'roll back'.. As far as using transactions to undo the state of the  
database, let me know if that's possible.. All of our tests have  
their own transaction boundaries that they're applying. I don't want  
to undo that, but certainly if I could nest each test in a longer- 
running tx and then roll it back.. that could work.

Thanks in advance.

Phill