Transcript Chapter 5

Uma Gupta
Introduction to Information Systems
Chapter
5
Database
Design
and
Management
 2000 by Prentice Hall.
5-1
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
 2000 by Prentice Hall.
5-2
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.
5-3
The Data Hierarchy
Database
A collection of
interrelated
data
File
A group of
interrelated
records
Record
Field
Personal
Data File
Credit
History File
Transaction
Data File
Last Name
First Name
Address
Phone Number
SSN
Adams
Jefferson
George
Mary
123 Lancelot Dr.
1779 Washington Ave.
704-555-1234
704-555-6789
987-76-5432
123-45-6789
Jefferson
Mary
1779 Washington Ave.
704-555-6789
123-45-6789
Jefferson (Last Name)
Mary (First Name)
1779 Washington Ave. (Address)
704-555-6789 (Phone Number)
1234-56-789 (Social Security No.)
Byte
M A R Y
Bit
0 (or 1)
 2000 by Prentice Hall.
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Database Management
System (DBMS)
A group of programs that helps
to create, process, store,
retrieve, control, maintain, and
manage data.
 2000 by Prentice Hall.
5-5
The Four Main DBMS
Components
DBMS
Data Definition
Language
Language to
create and
modify data
Data
Manipulation
Language
Data Dictionary
Reports and
Utilities
Language to
process and
update data
An electronic
document
that provides
detailed
information
about each
and every
piece of data
in the
database
Software that
generates reports
and makes the
database userfriendly
 2000 by Prentice Hall.
5-6
Data Manipulation
Language (DML)
A language that processes and
updates data.
 2000 by Prentice Hall.
5-7
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.
 2000 by Prentice Hall.
5-8
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
 2000 by Prentice Hall.
5-9
Data Dictionary
A data dictionary describes each piece of data in a business and describes in
detail the characteristics of the data
 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
 2000 by Prentice Hall.
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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
 2000 by Prentice Hall.
5-11
The Three Types of
Relationships among Entities
Priya
1:1
Priya’s
Mother
Peter
Paula
Priya
1:many
Pam
Customer A
MasterCard
Customer B
Visa
American
Express
Customer C
Many:Many
 2000 by Prentice Hall.
Customer D
Customer E
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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
 2000 by Prentice Hall.
5-13
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
 2000 by Prentice Hall.
5-14
Data Warehouse
 A large database that is a collection
of smaller databases containing
useful data designed to support
decision making.
 2000 by Prentice Hall.
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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.
 2000 by Prentice Hall.
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Data Mining
The automated analysis of large
data sets to find patterns and
trends that might otherwise go
undiscovered.
 2000 by Prentice Hall.
5-17
Distributed Databases
A database distributed over
computer hardware located in
different geographical areas.
 2000 by Prentice Hall.
5-18
Different Ways to Distribute
Databases
CUSTOMER
DATABASE
Duplicate
copies of the
customer
database in
different
locations
New York
Dividing a
customer
database
and locating
portions in
relevant
locations
CUSTOMER
DATABASE
Chicago
Raleigh
Portland
 2000 by Prentice Hall.
5-19
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
 2000 by Prentice Hall.
5-20
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
 2000 by Prentice Hall.
5-21
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
 2000 by Prentice Hall.
5-22
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
 2000 by Prentice Hall.
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