SQL For Dummies®

Chapter 1. Relational Database Fundamentals

In This Chapter

• Organizing information

• Defining database

• Defining DBMS

• Comparing database models

• Defining relational database

• Considering the challenges of database design

SQL (pronounced ess‐que‐ell, not see'qwl) is an industry‐standard language specifically designed to enable people to create databases, add new data to databases, maintain the data, and retrieve selected parts of the data. Various kinds of databases exist, each adhering to a different conceptual model. SQL was originally developed to operate on data in databases that follow the relational model. Recently, the international SQL standard has incorporated part of the object model, resulting in hybrid structures called object‐relational databases. In this chapter, I discuss data storage, devote a section to how the relational model compares with other major models, and provide a look at the important features of relational databases.

Before I talk about SQL, however, I need to nail down what I mean by the term database. Its meaning has changed as computers have changed the way people record and maintain information.

Keeping Track of Things

Today, people use computers to perform many tasks formerly done with other tools. Computers have replaced typewriters for creating and modifying documents. They've surpassed electromechanical calculators as the best way to do math. They've also replaced millions of pieces of paper, file folders, and file cabinets as the principal storage medium for ...