Introduction to Databases
Databases play an enormous role in almost every aspect of our lives. Think of the amount of credit card transactions that take place during a given day, from receiving authorization at the point of sale to applying the purchase to your credit card to the store receiving payment from the credit card company. There are many stores, banks, and credit cards involved. Databases are all around you. You only need to learn how to view the world in terms of databases.
Think of your favorite department store. Chances are the one you shop at is just one of several in the chain. And these stores are probably located in different states. Databases manage this information.
Inside the store there are different departments: Ladies, Mens, and Electronics, to name a few. Within Electronics, there are different categories called classes, and these might be represented by radios, televisions, CDs, and DVDs. More databases.
And within any given class—CDs, for example—there are subclasses like jazz, rock, country, and classical. Within rock there are bands, and within bands there are recordings.
Get the idea? Even more databases.
This structure categorizes different kinds of information at almost every level of the store. It is essential to maintaining order and accuracy.