Enterprise manage information systems 6th by laudon ch07

Chapter 7

Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Managing Data Resources

7.1

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Objectives

1. Why do businesses have trouble finding the
information they need in their information
systems?
2. How does a database management system help
businesses improve the organization of their
information?

7.2

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Objectives

3. How do the principal types of database models
affect the way businesses can access and use
information?
4. What are the managerial and organizational
requirements of a database environment?
5. What new tools and technologies can make
databases more accessible and useful?

7.3

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Management Challenges

1. Organizational obstacles to a database
environment
2. Cost/benefit considerations

7.4

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Organizing Data in a Traditional File Environment
File Organization Terms and Concepts

• Bit: Smallest unit of data; binary digit (0,1)
• Byte: Group of bits that represents a single character
• Field: Group of words or complete number
• Record: Group of related fields
• File: Group of records of the same type

7.5

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Organizing Data in a Traditional File Environment
File Organization Terms and Concepts

• Database: Group of related files
• Entity: Person, place, thing, or event about which
information must be kept
• Attribute: A piece of information describing a
particular entity
• Key field: Field that uniquely identifies every
record in a file

7.6

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Organizing Data in a Traditional File Environment
The data hierarchy

Figure 7-1
7.7

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Organizing Data in a Traditional File Environment
Entities and attributes

Figure 7-2
7.8

© 2005 by Prentice Hall

Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Organizing Data in a Traditional File Environment
Problems with the Traditional File Environment

• Data redundancy
• Program-data dependence
• Lack of flexibility
• Poor security
• Lack of data-sharing and availability

7.9

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

Organizing Data in a Traditional File Environment
Traditional file processing

Figure 7-3
7.10

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Essentials of Management Information Systems, 6e

Chapter 7 Managing Data Resources

The Database Approach to Data Management
Database Management Systems

Database
• Collection of centralized data
• Controls redundant data
• Data stored so as to appear to users in one location
• Services multiple application

7.11

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
The contemporary database environment

Figure 7-4
7.12

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Database Management Systems

Database Management System (DBMS)
• Creates and maintains databases
• Eliminates requirement for data definition
statements
• Acts as interface between application programs
and physical data files
• Separates logical and physical views of data

7.13

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Database Management Systems

Three Components to a DBMS
1. Data definition language: Formal language
programmers use to specify structure of database
2. Data manipulation language: For extracting data
from database, e.g. SQL
3. Data dictionary: Tool for storing, organizing
definitions of data elements and data

characteristics

7.14

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Sample data dictionary report

Figure 7-5
7.15

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Database Management Systems

How a DBMS Solves Problems of a
Traditional File Environment
•
•
•

•
•

7.16

Reduces data redundancy
Eliminates data inconsistency
Uncouples programs from data
Increases access and availability of data
Allows central management of data, data use, and
security
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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Types of Databases

Relational DBMS
• Represents data as two-dimensional tables called
relations
• Relates data across tables based on common data
element
• Examples: DB2, Oracle, MS SQL Server

7.17

© 2005 by Prentice Hall

Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
The relational data model

Figure 7-6
7.18

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Types of Databases

Three Basic Operations in a Relational Database
• Select: Creates subset of rows that meet specific
criteria
• Join: Combines relational tables to provide users
with information
• Project: Enables users to create new tables
containing only relevant information

7.19

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
The three basic operations of a relational DBMS

Figure 7-7
7.20

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Types of Databases

Hierarchical DBMS
• Older system presenting data in tree-like structure
• Models one-to-many parent-child relationships
• Found in large legacy systems requiring intensive highvolume transactions: Banks; insurance companies
• Examples: IBMs IMS

7.21

© 2005 by Prentice Hall

Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
A hierarchical database for a human resources system

Figure 7-8
7.22

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Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Types of Databases

Network DBMS
• Older logical database model
• Models many-to-many parent-child relationships
• Example: Student – course relationship: Each
student has many courses; each course has many
students

7.23

© 2005 by Prentice Hall

Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
The network data model

Figure 7-9
7.24

© 2005 by Prentice Hall


Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources

The Database Approach to Data Management
Types of Databases

Disadvantages of Hierarchical and
Network DBMS
• Outdated
• Less flexible compared to RDBMS
• Lack support for ad-hoc and English language-like
queries
7.25

© 2005 by Prentice Hall