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8 M anagem entInform ation System s, Second Edition Effy O z Chapter 8 Chapter 8 Data and Knowledge Data and Knowledge Management Management
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Management Information Systems, Second EditionEffy Oz
Chapter 8Chapter 8Data and Knowledge Data and Knowledge ManagementManagement
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Learning ObjectivesLearning Objectives
When you finish this chapter, you will
Know the difference between traditional file organization methods and the database approach.
Know how database management systems are used to construct databases, populate them with data, and manipulate the data to produce information.
Be familiar with the different database models and the advantages and disadvantages of each model.
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Learning ObjectivesLearning Objectives
Know the most important features and operations of a relational database.
Understand how databases are changing business operations across industries and what impact they might have on our personal lives.
Understand the concepts of data warehousing and data-mining and their use in business.
Recognize the need for knowledge storage and management and be able to give examples of the ways knowledge is managed in organizations.
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Managing Digital DataManaging Digital Data
The Traditional File Approach Disadvantages
Program/Data Dependency Data Redundancy Data Integrity
Moving to Databases Database Management System (DBMS)
Queries: Request data from specified fields Security: Giving users different views addresses
security issue
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Managing Digital DataManaging Digital Data
Figure 8.1 The layout of a personnel file in traditional file organization.
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Managing Digital DataManaging Digital Data
Figure 8.2 Different information making up a student record retained in three different sites.
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Managing Digital DataManaging Digital Data
Figure 8.3 Data hierarchy
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Managing Digital DataManaging Digital Data
Figure 8.4 Different database views reveal different combinations of data
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Managing Digital DataManaging Digital Data
Figure 8.5 Different views of one employee database
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Managing Digital DataManaging Digital Data
Traditional Files vs. Databases: Pros and Cons
Traditional File Advantages Simplicity Efficiency Customization
Database Advantages Reduced data redundancy Application/data independence Better control Flexibility
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Database ModelsDatabase Models
Figure 8.6 Advantages and disadvantages of database models
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Database ModelsDatabase Models
The Hierarchical Model
Records are related hierarchically -- each category is a subcategory of the next level up
Disadvantages of hierarchical databases To retrieve a record, a user must start at the root
and navigate the hierarchy. If a link is broken, the entire branch is lost. Requires considerable data redundancy because
child records can have only one parent
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Database ModelsDatabase Models
Figure 8.7 A schematic diagram of a hierarchical database (a) and a sample part of a hierarchical database showing relationships among different records (b)
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Database ModelsDatabase Models
The Network Model Allows a record to be linked to more than
one parent
Supports many-to-many (N:M) relationships
Advantage of the network model Reduced data redundancy
Disadvantages of the network model Complicated to build and difficult to maintain Difficult to navigate
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Database ModelsDatabase Models
Figure 8.8 A schematic diagram of a network database (a) and a sample of part of a network database showing relationships among different records (b)
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Database ModelsDatabase Models
The Relational Model
Consists of tables; links among entities are maintained with foreign keys
Advantages of relational databases Same advantages of a network database without
the complications. Easier to conceptualize and maintain. Virtually all DBMSs offered for microcomputers
accommodate the relational model.
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Database ModelsDatabase Models
Figure 8.9 A schematic diagram of a relational database (a) and a sample part of a relational database showing different tables (b)
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Database ModelsDatabase Models
Keys Fields whose values identify records for
display or processing.
Primary key Uniquely identifies a record
Linking
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Database ModelsDatabase Models
The Object-Oriented Structure Affords maintenance of data along with the applications that
process them
Entity-Relationship Diagrams Conceptual blueprint of a database
Graphical representation of all entity relationships
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Database ModelsDatabase Models
Figure 8.10 An entity-relationship diagram
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Components of Database Components of Database Management SystemsManagement Systems
The Schema Describes the structure of the database
The Data Dictionary (Metadata) Maintains all information supplied by the
developer when constructing the schema
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Components of Database Components of Database Management SystemsManagement Systems
Figure 8.12 A typical data dictionary for a staff file
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Figure 8.13 Data definition language to create a schema in NOMAD
Components of Database Components of Database Management SystemsManagement Systems
Data Definition Language (DDL) Used to construct the schema
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Components of Database Components of Database Management SystemsManagement Systems
Data Manipulation Language (DML) Used to query the database
Figure 8.14 A Paradox query by example
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Relational OperationsRelational Operations
Data Manipulation Select, Project, Join
Structured Query Language (SQL) International standard DDL and DML for
relational DBMS.
Advantages of using SQL Users do not need to learn different DDLs and DMLs. SQL can be embedded in widely used 3rd generation
languages, increasing efficiency and effectiveness. Programmer not forced to rewrite statements since SQL
statements are portable.
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Relational OperationsRelational Operations
Figure 8.15 A join table of professors and their students
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Popular Database Popular Database Management SystemsManagement Systems
DATABASE MODEL PRODUCT VENDOR HARDWAREHierarchical Focus Information Builders International Mainframe/PC
IMS IBM MainframeRamis Online Software International Mainframe
Network ADABAS Software AG of North America MainframeImage Hewlett-Packard Mainframe
Relational Access Microsoft PCDB2 IBM MainframedBASE V Borland International PCEDA/SQL Information Builders International PCFoxPro Microsoft PCIngres Ask Group PCNOMAD Must Software International Mainframe/PCOracle Oracle Mainframe/PCParadox Borland International PCRbase Microrim PCSQL/DS IBM MainframeSQL Server Microsoft PCSybase Sybase PC
Object-Relational ObjectStore Object Design PCUniversalServer
Informix PC
Illustra Informix PC
Figure 8.16 Popular DBMSs
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Database ArchitectureDatabase Architecture
Distributed Databases
Replication Full copy of the entire database is stored at all sites
Fragmentation Parts of database are stored where they are most often
accessed
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Database ArchitectureDatabase Architecture
Figure 8.17 A replicated database: each computer holds a copy of the entire database
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Database ArchitectureDatabase Architecture
Figure 8.18 A fragmented database: each computer holds only the part of the database that is most frequently accessed by the local users
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Database ArchitectureDatabase Architecture
Shared Resource and Client/Server Systems
Four basic client/server models Applications run at a server Applications run on local PCs Applications run on both the local PCs and the
server Applications and key elements of the database
are split between the PCs and the server
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Database ArchitectureDatabase Architecture
Figure 8.19 Shared resource and client/server architectures
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Web DatabasesWeb DatabasesDatabases on the Web
Catalogs Libraries Directories Client lists and profiles
When linking a database to the Internet, consider
Which application to use How to ensure Web surfers do not interfere with
database updates How to maintain security
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Data WarehousingData Warehousing Data warehouse
Collection of data that supports management decision making
Phases in Building a Data Warehouse Extraction Phase Cleansing Phase Loading Phase
Data Mining Selecting, exploring, and modeling data to discover unknown relationships
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Data WarehousingData Warehousing
Figure 8.20 Data are warehoused for analysis and reporting
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Data-MiningData-Mining
Figure 8.21 Potential applications of data-mining
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Knowledge ManagementKnowledge Management
The attempt by organizations to:
Transfer knowledge into databases
Filter and separate the most relevant knowledge
Organize knowledge in databases that either Allow other employees to easily access the knowledge “Push” specific knowledge to employees based on
their prespecified needs
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Ethical and Societal IssuesEthical and Societal IssuesA Too-Risky Info HighwayA Too-Risky Info Highway
Out of Hand -- Out of Control
DBMSs allow organizations to collect, maintain, and sell vast amounts of private personal data easily.
Where is the Information Going?
Many consumers provide information daily without being aware of where it is actually going.
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Ethical and Societal IssuesEthical and Societal IssuesA Too-Risky Info HighwayA Too-Risky Info Highway
Personal Data Matched, Sliced , and Diced Pieces of personal data may be matched and put
together to reveal private life in unexpected ways.
Error Propagation In case of errors, it may be impossible to trace your
data to all organizations that have it.
The Upside Database technology enables better and faster
services.
