The previous chapters discussed databases in general terms. Chapter 1 explained the general goals of database design. Chapter 2 described some of the many kinds of databases that you might decide to use.
With this chapter the book starts to focus on a particular kind of database: the relational database. Relational databases are very powerful, are the most commonly used kind of database in computer applications today, and are the focus of the rest of this book.
Before you can start learning how to properly design a relational database, you must understand the basic concepts and terms that underlie relational databases.
This chapter provides an introduction to relational databases. It explains the major ideas and terms that you need to know before you can start designing and building relational databases.
In this chapter, you learn about relational database terms such as:
Table and relation
Record, row, and tuple
Column, field, and attribute
Constraint, key, and index
Finally, you learn about the operations that you can use to get data out of a relational database.
Relational databases play a critical role in many important (that is, money-related) computer applications. As is the case whenever enormous amounts of money are at stake, people have spent a huge amount of time and effort building, studying, and refining relational databases. Database researchers usually approach relational databases from one of three points of ...