7.1 © 2004 by Prentice Hall Management Information Systems 8/e Chapter 7 Managing Data Resources 7 7 MANAGING DATA DATARESOURCES Chapter

7.1 © 2004 by Prentice Hall

Management Information Systems 8/eManagement Information Systems 8/eChapter 7 Managing Data ResourcesChapter 7 Managing Data Resources77

MANAGINGMANAGING

DATA DATA

RESOURCESRESOURCES

Chapter


Management Information Systems 8/eManagement Information Systems 8/eChapter 7 Managing Data ResourcesChapter 7 Managing Data Resources

• Why do businesses have trouble finding Why do businesses have trouble finding the information they need in their the information they need in their information systems?information systems?

• How does a database management system How does a database management system help businesses improve the organization help businesses improve the organization of their information?of their information?

OBJECTIVES



• How do the principal types of database How do the principal types of database models affect the way businesses can models affect the way businesses can access and use information?access and use information?

• What are the managerial and What are the managerial and organizational requirements of a data-organizational requirements of a data-base environment?base environment?

• What new tools and technologies can What new tools and technologies can make databases more accessible and make databases more accessible and useful?useful?

OBJECTIVES



• Organizational obstacles to a Organizational obstacles to a database environmentdatabase environment

• Integrating data and ensuring Integrating data and ensuring qualityquality

MANAGEMENT CHALLENGES



File Organization Terms and Concepts

• Bit:Bit: Smallest unit of data; binary digit (0,1) Smallest unit of data; binary digit (0,1)

• Byte:Byte: Group of bits that represents a single Group of bits that represents a single charactercharacter

• Field:Field: Group of words or a complete Group of words or a complete numbernumber

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT



• Record:Record: Group of related fieldsGroup of related fields

• File:File: Group of records of same typeGroup of records of same type

• Database:Database: Group of related filesGroup of related files





Data Hierarchy in a Computer System

Figure 7-1




• Entity:Entity: Person, place, thing, event about Person, place, thing, event about which information is maintainedwhich information is maintained

• Attribute:Attribute: Description of a particular entity Description of a particular entity

• Key field:Key field: Identifier field used to retrieve, Identifier field used to retrieve, update, sort a recordupdate, sort a record





Figure 7-2

Entitities and Attributes





• Data redundancyData redundancy

• Program-Data dependenceProgram-Data dependence

• Lack of flexibilityLack of flexibility

• Poor securityPoor security

• Lack of data-sharing and availabilityLack of data-sharing and availability

Problems with the Traditional File Environment



Traditional File Processing

Figure 7-3




THE DATABASE APPROACH TO DATA MANAGEMENT

• Creates and maintains databasesCreates and maintains databases

• Eliminates requirement for data definition Eliminates requirement for data definition statementsstatements

• Acts as interface between application Acts as interface between application programs and physical data filesprograms and physical data files

• Separates logical and physical views of Separates logical and physical views of datadata

Database Management System (DBMS)



The Contemporary Database Environment

Figure 7-4




Components of DBMS

• Data definition language: Data definition language: Specifies Specifies content and structure of database and content and structure of database and defines each data elementdefines each data element

• Data manipulation language:Data manipulation language:Manipulates data in a databaseManipulates data in a database

• Data dictionary:Data dictionary: Stores definitions of Stores definitions of data elements, and data characteristicsdata elements, and data characteristics




Sample Data Dictionary Report


Figure 7-5



Types of Databases

• Relational DBMSRelational DBMS

• Hierarchical and Network DBMSHierarchical and Network DBMS

• Object-Oriented DatabasesObject-Oriented Databases




Relational DBMS

• Represents data as two-dimensional tables Represents data as two-dimensional tables called relationscalled relations

• Relates data across tables based on common Relates data across tables based on common data elementdata element

• Examples: DB2, Oracle, MS SQL ServerExamples: DB2, Oracle, MS SQL Server




Figure 7-6

Relational Data Model




Three Basic Operations in a Relational Database

• Select:Select: Creates subset of rows that meet Creates subset of rows that meet specific criteriaspecific criteria

• Join:Join: Combines relational tables to provide Combines relational tables to provide users with informationusers with information

• Project:Project: Enables users to create new tables Enables users to create new tables containing only relevant informationcontaining only relevant information




Figure 7-7


Three Basic Operations in a Relational Database



Hierarchical and Network DBMS

Hierarchical DBMSHierarchical DBMS

• Organizes data in a tree-like structureOrganizes data in a tree-like structure

• Supports one-to-many parent-child Supports one-to-many parent-child relationshipsrelationships

• Prevalent in large legacy systemsPrevalent in large legacy systems




Hierarchical DBMS

Figure 7-8





Network DBMSNetwork DBMS

• Depicts data logically as many-to-many Depicts data logically as many-to-many relationshipsrelationships




Figure 7-9

Network DBMS




DisadvantagesDisadvantages

• OutdatedOutdated

• Less flexible compared to RDBMSLess flexible compared to RDBMS

• Lack support for ad-hoc and English Lack support for ad-hoc and English language-like querieslanguage-like queries





• Object-oriented DBMS:Object-oriented DBMS: Stores data and Stores data and procedures as objects that can be procedures as objects that can be retrieved and shared automatically retrieved and shared automatically

• Object-relational DBMS:Object-relational DBMS: Provides Provides capabilities of both object-oriented and capabilities of both object-oriented and relational DBMSrelational DBMS

Object-Oriented Databases




Basic SQL CommandsBasic SQL Commands

• SELECT: Specifies columnsSELECT: Specifies columns

• FROM: Identifies tables or viewsFROM: Identifies tables or views

• WHERE: Specifies conditions WHERE: Specifies conditions

Querying Databases: Elements of SQL




Results of SELECT Statement

Figure 7-10





Results of Conditional Selection

Figure 7-11

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22.506.00

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Figure 7-12

Projection from Joining PART and SUPPLIER Tables



• Conceptual design:Conceptual design: Abstract model of Abstract model of database from a business perspectivedatabase from a business perspective

• Physical design:Physical design: Detailed description of Detailed description of business information needsbusiness information needs

Designing Databases

CREATING A DATABASE ENVIRONMENT



• Entity-relationship diagram:Entity-relationship diagram: Methodology Methodology for documenting databases illustrating for documenting databases illustrating relationships between database entitiesrelationships between database entities

• Normalization:Normalization: Process of creating small Process of creating small stable data structures from complex groups stable data structures from complex groups of dataof data


Designing Databases




Figure 7-13




Figure 7-14




An Normalized Relation of ORDER

Figure 7-15



Centralized databaseCentralized database

• Used by single central processor or multiple Used by single central processor or multiple processors in client/server networkprocessors in client/server network

Distributing Databases




Distributed databaseDistributed database

• Stored in more than one physical locationStored in more than one physical location

• Partitioned database Partitioned database

• Duplicated databaseDuplicated database

Distributing Databases




Distributed Databases

Figure 7-16




Management Requirements for Database Systems

Key elements in a database environment:Key elements in a database environment:

• Data AdministrationData Administration

• Data Planning and Modeling MethodologyData Planning and Modeling Methodology

• Database Technology and ManagementDatabase Technology and Management

• UsersUsers




Figure 7-17


Management Requirements for Database Systems



Multidimensional Data Analysis

On-line analytical processing (OLAP)On-line analytical processing (OLAP)

• Multidimensional data analysisMultidimensional data analysis

• Supports manipulation and analysis of Supports manipulation and analysis of large volumes of data from multiple large volumes of data from multiple dimensions/perspectivesdimensions/perspectives

DATABASE TRENDS



Multidimensional Data Model

Figure 7-18

DATABASE TRENDS



Data warehouseData warehouse

• Supports reporting and query toolsSupports reporting and query tools

• Stores current and historical data Stores current and historical data

• Consolidates data for management Consolidates data for management analysis and decision makinganalysis and decision making

Data Warehousing and Datamining

DATABASE TRENDS



Components of a Data Warehouse

DATABASE TRENDS

Figure 7-19



Data martData mart

• Subset of data warehouse Subset of data warehouse

• Contains summarized or highly focused Contains summarized or highly focused portion of data for a specified function or portion of data for a specified function or group of usersgroup of users


DATABASE TRENDS



DataminingDatamining

• Tools for analyzing large pools of data Tools for analyzing large pools of data

• Find hidden patterns and infer rules to Find hidden patterns and infer rules to predict trendspredict trends


DATABASE TRENDS



• Improved and easy accessibility to Improved and easy accessibility to informationinformation

• Ability to model and remodel the dataAbility to model and remodel the data

Benefits of Data Warehouses

DATABASE TRENDS



Databases and the Web

Hypermedia databaseHypermedia database

• Organizes data as network of nodesOrganizes data as network of nodes

• Links nodes in pattern specified by userLinks nodes in pattern specified by user

• Supports text, graphic, sound, video and Supports text, graphic, sound, video and executable programsexecutable programs

DATABASE TRENDS



A Hypermedia Database

Figure 7-20

DATABASE TRENDS



Database serverDatabase server

• Computer in a client/server environment Computer in a client/server environment runs a DBMS to process SQL statements runs a DBMS to process SQL statements and perform database management tasksand perform database management tasks

Application serverApplication server

• Software handling all application Software handling all application operationsoperations

Databases and the Web

DATABASE TRENDS



Linking Internal Databases to the Web

Figure 7-21

DATABASE TRENDS


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7.1 © 2004 by Prentice Hall Management Information Systems 8/e Chapter 7 Managing Data Resources 7 7 MANAGING DATA DATARESOURCES Chapter