What is the meaning of Transaction?

I've been reading about "Java Transaction"开发者_如何学运维 , and i've been confused about what's it? and what's useful in?

You can google around and find pages like this: http://www.java-tips.org/java-ee-tips/enterprise-java-beans/introduction-to-the-java-transactio.html

but the bottom line is: a transaction is a set of operations which must all succeed or all fail and be reversed (rolled back).

The obvious example is banking: if you transfer money from savings to checking, both updates had better occur, or neither, otherwise there will be an error.

I would say the best place to start are:

http://en.wikipedia.org/wiki/Transaction_processing

http://en.wikipedia.org/wiki/ACID

Thanks, Nitin