Beginning T-SQL with Microsoft® SQL Server® 2005 and 2008

Chapter 10. Transactions

We live in a transactional world. In the not-too-distant future, some of us may be trying to explain the concept of using cash to our grandchildren: "Some people carried paper and small metal disks in their pockets. They had pictures of dead government leaders on them and each one was worth a different value. When you wanted to purchase something, you would hand the paper or metal money to a store clerk in exchange for the stuff you bought." What a strange idea!

In the physical world, things move from one place to another. Like the money the customer hands to the store clerk, this transfer of ownership is a simple concept that even the least sophisticated members of the animal kingdom comprehend. In recent decades, however, mankind has managed to change the mechanics of moving things from one place to another within the information world. For example, on payday, chances are that you don't actually receive real money directly from your employer. I haven't seen a real paycheck for many years. My bank account balance is magically increased as my employer's contracted payroll service provider posts a credit to my bank account. Of course, this happens right before the balance decreases due to a similar transaction performed by my mortgage company.

We perceive that things such as money, files, and data move from one place to another. Although the paradigm is the same—modeled after things in the physical world—it's really all made up. We understand that data doesn't ...