Beginning Transact-SQL with SQL Server 2000 and 2005

9

Data 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: “Most people carried paper and small metal disks around with them, and each one had a different a 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 being handed to the store clerk by the customer, this transfer of ownership is a simple concept that even the least sophisticated members of the animal kingdom comprehend. In recent decades, though, 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 money directly from your employer. I don't even get a paycheck. My bank account balance is magically increased as my employer's contracted payroll company posts a credit to my 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 really move. It gets copied from storage and the new copy is inserted into a new storage ...