TIP: Nested Stored Procedure Calls with SQL Server Transactions
September 2, 2008[From Developer.com]
When developing data-driven software, it is often vital that you manage transactions to ensure that unexpected errors do not corrupt the database. Transactions allow you to group sets of related database calls in a single, logical unit-of-work. The classic example of debiting one bank account, then crediting another, is often used to illustrate the importance of transactions. If the process blows up somewhere in the middle, you want everything put back as it was initially. It is the 'all or nothing' principle.
The article continues at http://www.developer.com/db/article.php/3768671