Transcript Managing the Digital Firm

Essentials of Management Information Systems, 6e
Chapter 7
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
Outlines
1. Challenges to access information using
traditional file management technologies.
2. Database management systems.
3. Managerial and organizational requirements for
implementing a database environment
successfully.
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© 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
• 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
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© 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
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© 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
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© 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
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© 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
7.7
© 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
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© 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: The presence of duplicate data
in multiple data files so that the same data are
stored in more than one place or location.
– Waste storage resources
– Data inconsistency: the same attribute having
different values (loose user confidence).
7.9
© 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
• Program-data dependence: Program changes lead
to data changes.
– 2-digit versus 4-digit year
– Sequence in a record
– Delimited character
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© 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
• Lack of flexibility
– Data merge
– Ad hoc reports
• Poor security
– Theft of data can occur in any department
without the knowledge of managers
• Lack of data-sharing and availability
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© 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
• Collection of centralized data
• Controls redundant data
• Data stored so as to appear to users in one location
• Services multiple application
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
The Database Approach to Data Management
The contemporary database environment
Figure 7-4
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© 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
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© 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
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
The Database Approach to Data Management
Sample data dictionary report
Figure 7-5
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© 2005 by Prentice Hall
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
•
•
•
•
•
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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
© 2005 by Prentice Hall
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 (the power of RDBMS)
• Examples: DB2, Oracle, MS SQL Server
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© 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
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© 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
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© 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
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© 2005 by Prentice Hall
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
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© 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
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© 2005 by Prentice Hall
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
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© 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
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© 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
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
The Database Approach to Data Management
Types of Databases
Object-Oriented Databases (OODBMS)
• Stores data and procedures as objects
• Better able to handle graphics and recursive data
• Data models more flexible
• Slower than RDBMS
• Hybrid: object-relational DBMS
7.27
© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Designing Databases
Two Design Phases in Creating Database
• Conceptual (logical) design: Abstract model
of database from business perspective
• Physical design: How the database is
actually arranged on direct access storage
devices
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Designing Databases
Conceptual Database Design
• Identifies relationships between data elements
• Identifies most efficient way to group data
elements
• Identifies redundant data elements
• Identifies grouping of data elements needed for
specific applications
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Designing Databases
Entity-Relationship Diagram
A methodology for documenting databases that
illustrates the relationship between various
elements in the database
Normalization
The process of creating small, stable, and adaptive
data structures from complex groups of data when
designing a relational database
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
An entity-relationship diagram
Figure 7-10
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
An unnormalized relation for ORDER
Figure 7-11
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
A normalized relation for ORDER
Figure 7-12
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Distributing Databases
Distributed Database
• Pros:
– Partitioned or replicated to more than one location
– Increases service and responsiveness
– Reduces vulnerability of single, massive central site
• Cons:
– Depend on telecommunication lines
– Pose security risks through distribution of sensitive data
– Central data must be updated or justified with local data
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Distributed databases
Figure 7-13
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Key organizational elements in the database environment
Figure 7-14
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Management Requirements for Database Systems
Data Administration
•
•
•
•
Develop information policy
Define information requirements
Plan for data
Oversee logical database design and database
dictionary development
• Monitor use of information
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Management Requirements for Database Systems
Data Planning and Modeling Methodology
• Enterprise-wide planning for data
• Enterprise Analysis: Identify key entities,
attributes, and relationships that constitute the
organization’s data
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Creating a Database Environment
Management Requirements for Database Systems
Database Technology, Management,
and Users
• Databases require DBMS software and staff
• Database design group defines and organizes structure and
content of database
• Database administration: establish physical database,
logical relations, access rules
• Permit non-professional access to database through SQL
• Devote more resources to end-user training
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Multidimensional Data Analysis
Online Analytical Processing (OLAP)
• Multidimensional data analysis
– Enables users to view the same data in different ways
using multiple dimensions
– Each aspect of information – product, price, region –
represents a different dimension
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Multidimensional data model
Figure 7-15
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Data Warehouses and Datamining
• Data warehouse: Stores current and historical data
for reporting, analysis
• Data mart: Subset of data warehouse with
summary of data for specific users
• Datamining: Techniques to find hidden patterns,
relationships in large pools of data to infer rules
for predicting future trends
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Components of a data warehouse
Figure 7-16
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Data Warehouses and Datamining
Benefits of Data Warehouses
• Improved information and accessibility
• Ability to model and remodel data
• Enable access to data without affecting
performance of underlying operational legacy
systems
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Window on Management
Data Reveal New Sales Opportunities
• How did the use of data warehouses and
datamining help management at these companies
make better decisions?
• What value do these systems provide?
7.45
© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Data Warehouses and Datamining
Hypermedia database
• Organizes data as network of nodes
• Links nodes in pattern specified by user
• Supports text, graphic, sound, video and
executable programs
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
A hypermedia database
Figure 7-17
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Databases and the Web
Linking Internal Databases to the Web
• Database server:
– Hosts DBMS
– Receives SQL requests
– Provides required data
• Middleware:
– Works between Web server and DBMS to take requests
– Handles connectivity to database
– Can be application server or CGI scripts
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Linking internal databases to the Web
Figure 7-18
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Databases and the Web
Advantages to Web Access to Databases
• Browser software easy to use; little training
• Web interface requires no changes to internal
database
• Costs less than custom interfaces
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© 2005 by Prentice Hall
Essentials of Management Information Systems, 6e
Chapter 7 Managing Data Resources
Database Trends
Window on Technology
Web Access for Royal Bank Statements
Pays Off
• What are the business benefits of providing a Web
interface for the Bankbook Reconstruct
application?
• What value does this application provide the
company and its customers?
7.51
© 2005 by Prentice Hall