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Chapter 5

Uma GuptaIntroduction to Information Systems

DatabaseDesign and

Management

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Learning Objectives

After studying this chapter, you will be able to:

Explain how data are stored and managed in a database

Describe a database management system (DBMS) and its components

Outline how structured query languages affect decision making

Describe data models Discuss data warehousing and data mining Explain how distributed databases help organizations

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Three Key Principles Guide Database Creation and Use

The main purpose of databases is to help a company become so fast, responsive, and useful to customers that it becomes the “company of choice.”

Databases should help decision makers assess how their decisions influence the overall health of the business. The typical byproduct is more committed involvement to the business and the decision-making process.

Databases should deliver relevant, timely information in a way that meets users’ needs. Information that is too much, too little, too soon, or too late will doom the communication process.

2000 by Prentice Hall. 5-4

The Data Hierarchy

Last Name

AdamsJefferson

First Name Address

GeorgeMary

123 Lancelot Dr.1779 Washington Ave.

Phone Number

704-555-1234704-555-6789

SSN

987-76-5432123-45-6789

Jefferson Mary 704-555-67891779 Washington Ave. 123-45-6789

FileA group ofinterrelatedrecords

Record

Field

Byte

Bit

DatabaseA collection ofinterrelateddata

Jefferson (Last Name)Mary (First Name)1779 Washington Ave. (Address)704-555-6789 (Phone Number)1234-56-789 (Social Security No.)

M A R Y

0 (or 1)

PersonalData File

CreditHistory File

TransactionData File

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Database Management System (DBMS)

A group of programs that helps to create, process, store, retrieve, control, maintain, and manage data.

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The Four Main DBMS Components

Language to create andmodify data

Data Definition Language

Language toprocess and update data

DataManipulation Language

An electronicdocumentthat providesdetailedinformationabout eachand everypiece of datain the database

Data Dictionary

Software thatgenerates reportsand makes the database user-friendly

Reports and Utilities

DBMS

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Data Manipulation Language (DML)

A language that processes and updates data.

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Structured Query Language (SQL)

A language that deals exclusively with data, namely, data integrity, data manipulation, data access, data retrieval, data query, and data security.

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Data Languages

Data definition language A DBMS language used to create and modify

the data

Data manipulation language (DML) A language that processes and updates data

Structured query language (SQL) A language that deals exclusively with data,

namely, data integrity, data manipulation, data access, data retrieval, data query, and data security

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Data Dictionary

Location of the data (in what file the data are located) Size of the data (how many bytes) Range of acceptable values for each field Type of data (number, character, audio, etc.) Source of the data (where the data originated) Usage (who uses the data) Ownership (who has the right to view or modify the

data) Methods for accessing and securing data

A data dictionary describes each piece of data in a business and describes indetail the characteristics of the data

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Data Views

Logical view of data A view that shows the logical

relationship(s) between different pieces of data in a database

Physical view of data A view that shows how and where data

are physically stored in a storage medium

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The Three Types of Relationships among Entities

MasterCard

Visa

AmericanExpress

Customer A

Customer B

Customer C

Customer D

Customer E

PriyaPriya’sMother

Priya

Peter

Paula

Pam

1:1

Many:Many

1:many

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Data Models

Hierarchical Data Model Looks similar to an organizational chart Each record in a hierarchical model can have

only one parent Ideally suited to represent one-to-many

(1-M) relationships Network Model

Represents many-to-many relationships A record can have multiple parents in a network

model

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Data Models (cont.)

Relational Model Most popular type of data model A relational model is based on relations A relation is a table that satisfies three criteria

– Each cell in the table has one and only one value

– Each row in a table is unique

– All entries in a column must be of the same kind

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Data Warehouse

A large database that is a collection of smaller databases containing useful data designed to support decision making.

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Similarities and Differences between a Database and a Data Warehouse

In many, though not all cases, data warehouses are significantly larger than databases because the warehouses are often a collection of interrelated databases.

Databases are often updated frequently, some even instantaneously. Data warehouses are not.

Like databases, data warehouses support fast on-line queries and quick summaries for managers.

Data warehouses are ideal for large volumes of data because the software that supports them is designed to hold sizable amounts of data.

Databases are usually organized around a department, say public safety, or around a function, say marketing. Data warehouses, in contrast, are often designed to gain a view of the entire organization.

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Data Mining

The automated analysis of large data sets to find patterns and trends that might otherwise go undiscovered.

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Distributed Databases

A database distributed over computer hardware located in different geographical areas.

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Different Ways to Distribute Databases

CUSTOMERDATABASE

New York Chicago Raleigh Portland

CUSTOMERDATABASE

New Y

ork

Portla

nd

Chicago

RaleighDividing a customer database and locating portions in relevant locations

Duplicate copies of the customer database in different locations

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Guidelines for Database Management Success

Use the Database to Improve Decision Making Many companies collect mammoth amounts of data,

but few put them to good use By carefully analyzing data and taking appropriate

action a company can win and keep customers Recognize That Databases Are Competitive

Weapons for All Businesses Many companies are delving into public databases

with a fine-toothed comb to find valuable competitive information

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Guidelines for Database Management Success (cont.)

Design the Database to Meet Users’ Communication Needs The information in the database must be

simple and accessible to everyone involved in making decisions

Show Decision Makers How Their Choices Affect the Business Databases enable decision makers at all

levels of the business to see how their decisions affect the entire business

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Guidelines for Database Management Success (cont.)

Use the Database to Become Consumers’ Company of Choice Aligning IS and corporate goals is an important

business challenge A company must develop and integrate its databases

to support its business strategy in order to provide outstanding customer service

Plan for Appropriate Security A database with valuable data must be guarded Businesspeople must plan and budget for appropriate

security and expect to upgrade security as technology improves

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Guidelines for Database Management Success (cont.)

Plan for Database Maintenance Maintaining the database so that it

continues to meet the needs of end users is an important aspect of database development

Managers must allocate resources for database management and maintenance at the beginning of the development project