What's the best way to store historic data?

[Jane Jukowsky]

I have a business application (Hibernate over H2) consisting of 20 tables or so. I'd like to modify it to add a "wayback machine": given time and date, I want to allow user to see what data was there at the time. Is there an elegant way to do it? If I code it by hand, it sounds like my DDL is going to be overly complicated and sort of mind-boggling; maybe there is a 3rd party tool that does the same?

[Cameron Wallace McKenzie]

You might want to look at the Hibernate Envers project for versioning. Not sure if that's quite what you want, but perhaps. It tracks changed data.

It's a separate project right now, but becomes part of the GA release with Hibernate 3.5 and JPA2.0 support.