2000 by Prentice Hall. 5-1
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
2000 by Prentice Hall. 5-3
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