Database Reference
In-Depth Information
1. The Relational Database
A fish must swim three times—in water, in butter, and in wine.
—P
OLISH PROVERB
Topics Covered in This Chapter
The relational database has been in existence for more than 40 years. It spawned a
multibillion-dollar industry,isthemostwidelyusedtypeofdatabaseintheworldtoday,and
isanessentialpartofoureverydaylives.Itisverylikelythatyouareusingarelationaldata-
base every time you purchase goods online or at a local store, make travel plans with your
travel agent, check out topics at the library, or make a purchase on the Internet.
Before we delve into the design process, let's take a look at a brief history of the relational
database—where it came from, where it is now, and where it's likely to go in the future.
Types of Databases
What is a database? As you probably know, a database is an organized collection of data
used for the purpose of modeling some type of organization or organizational process. It
really doesn't matter whether you're using paper or a computer application program to col-
lect and store the data. As long as you're gathering data in some organized manner for a
specific purpose, you've got a database. Throughout the remainder of this discussion, we'll
assume that you're using an application program to collect and maintain your data.
Therearetwotypesofdatabasesindatabasemanagement,operationaldatabasesandanalyt-
ical databases.
Operational databases are the backbone of many companies, organizations, and institutions
throughout the world. This type of database is primarily used in online transaction process-
