O'Reilly logo

Information Systems by Efrem G. Mallach

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

145
Chapter 5
Data, Databases, and
Database Management
CHAPTER OUTLINE
e Database Concept
Operational Databases
Databases for Decision Making
Database Management Systems
Database Security
WHY THIS CHAPTER MATTERS
Computers do not make businesses successful. Intelligent use of information helps make
businesses successful. Computers are a tool in using information intelligently. Databases are
one of the two key technologies that make today’s intelligent uses of information practical.
To get the information we need when we need it, that information must be properly
organized. Proper organization makes it possible to retrieve information eciently, with-
out a lot of extra work; to control access to information, making it available to those who
need it but not to those who don’t; and to use this information in new, creative ways.
As a businessperson, you must be on the lookout for new ways to use information. Knowing
how computers organize information will help you do this. Knowing this will also help you
work with professional database designers to get the databases you need to do your work.
CHAPTER TAKE-AWAYS
As you read this chapter, focus on these key concepts to use on the job:
1. Databases help organizations become eective by allowing people and applications to
share common organizational information.
2. Most databases today use the relational model. Relational databases are exible. ey
can handle applications that were not foreseen when the database was rst set up.
146 Information Systems: What Every Business Student Needs to Know
3. Applications that involve data analysis and decision making may use other database
models.
4. Using databases requires database management soware to store and retrieve data on
behalf of users and applications.
THE DATABASE CONCEPT
A database is an organized collection of data about related items or concepts in the real
world.
At the lowest level, data consists of bytes, because bytes are the basic storage unit of
computers. Data made up of characters, such as names and addresses, ts naturally into
bytes. Other types of data are stored in bytes as well. Most business data consists primarily
of character strings.
ese bytes are grouped into elds or data elements. Each eld in a database contains
one data item that has meaning to the organization. A student’s family name may be a
eld in a university database. Other elds in that database may store the student’s major,
expected year of graduation, hometown, and all the other information universities keep
about their students (Figure 5.1).
Where you t in: The best way to organize data into elds is not always obvious. Should a
person’s name be stored as a unit or as family name and given name* separately? In a shoe
database, should size 8C be stored as one eld or as length (8) and width (C) in separate
elds? This decision should be made by people who know where the data will come from and
how it will be used. When that’s you, understanding database concepts will help you make
good choices.
A data eld might not consist of characters. A digital photograph in a driver’s license
record is a eld. So is a sound recording of a persons voice or a scan of the pattern of
*
It’s best to avoid using “rst name” and “last name,” since name order varies from one culture to another.
8 bits=1 byte
3 bytes=3 letters such as “abc
3 bytes=number from 0 to 16.7 million
3 bytes=color of one point on a screen
FIGURE 5.1 Bits forming bytes forming a character string, a number and a pixel.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required