Persistence 101A Learning Lounge course about persistence:
What matters is whether persistence is more or less Orthogonal.
See the Glossary entry about Orthogonal Persistence.
Lots of works done on Orthogonal Persistence at the University of St. Andrews, and spreading from there, to other places in Scotland or Australia.
Read something about Transactions in databases, concerns of Atomicity, etc.
NB: Persistent data structure are a nice way of implementing orthogonal persistence, and very great things to know (see Chris Okasaki's book), but they are really a different topic.
This page is linked from: Learning Lounge