chap01

© 2007 by Prentice Hall© 2007 by Prentice Hall 11

Chapter 1:Chapter 1:The Database The Database EnvironmentEnvironment

Modern Database Modern Database ManagementManagement

88thth Edition EditionJeffrey A. Hoffer, Mary B. Prescott, Jeffrey A. Hoffer, Mary B. Prescott,

Fred R. McFaddenFred R. McFadden

22Chapter 1 © 2007 by Prentice Hall© 2007 by Prentice Hall

ObjectivesObjectives Definition of termsDefinition of terms Explain growth and importance of databasesExplain growth and importance of databases Name limitations of conventional file Name limitations of conventional file

processingprocessing Identify five categories of databasesIdentify five categories of databases Explain advantages of databasesExplain advantages of databases Identify costs and risks of databasesIdentify costs and risks of databases List components of database environmentList components of database environment Describe evolution of database systemsDescribe evolution of database systems


DefinitionsDefinitions Database: organized collection of logically Database: organized collection of logically

related datarelated data Data: stored representations of meaningful Data: stored representations of meaningful

objects and eventsobjects and events Structured: numbers, text, datesStructured: numbers, text, dates Unstructured: images, video, documentsUnstructured: images, video, documents

Information: data processed to increase Information: data processed to increase knowledge in the person using the dataknowledge in the person using the data

Metadata: data that describes the properties Metadata: data that describes the properties and context of user dataand context of user data


Figure 1-1a Data in context

Context helps users understand data


Graphical displays turn data into useful information that managers can use for decision making and

interpretation

Figure 1-1b Summarized data


Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and

data context


Disadvantages of File Disadvantages of File ProcessingProcessing

Program-Data DependenceProgram-Data Dependence All programs maintain metadata for each file they useAll programs maintain metadata for each file they use

Duplication of DataDuplication of Data Different systems/programs have separate copies of the Different systems/programs have separate copies of the

same datasame data

Limited Data SharingLimited Data Sharing No centralized control of dataNo centralized control of data

Lengthy Development TimesLengthy Development Times Programmers must design their own file formatsProgrammers must design their own file formats

Excessive Program MaintenanceExcessive Program Maintenance 80% of information systems budget80% of information systems budget


Problems with Data Problems with Data DependencyDependency

Each application programmer must Each application programmer must maintain his/her own datamaintain his/her own data

Each application program needs to Each application program needs to include code for the metadata of each include code for the metadata of each filefile

Each application program must have its Each application program must have its own processing routines for reading, own processing routines for reading, inserting, updating, and deleting datainserting, updating, and deleting data

Lack of coordination and central controlLack of coordination and central control Non-standard file formatsNon-standard file formats


Figure 1-3 Old file processing systems at Pine Valley Furniture Company

Duplicate Data


Problems with Data Problems with Data RedundancyRedundancy

Waste of space to have duplicate dataWaste of space to have duplicate data Causes more maintenance headachesCauses more maintenance headaches The biggest problem: The biggest problem:

Data changes in one file could cause Data changes in one file could cause inconsistenciesinconsistencies

Compromises in Compromises in data integritydata integrity


SOLUTION: SOLUTION: The DATABASE ApproachThe DATABASE Approach

Central repository of shared dataCentral repository of shared data Data is managed by a controlling Data is managed by a controlling

agentagent Stored in a standardized, Stored in a standardized,

convenient formconvenient form

Requires a Database Management System (DBMS)


Database Management Database Management SystemSystem

DBMS manages data resources like an operating system manages hardware resources

A software system that is used to create, maintain, and provide controlled access to user databases

Order Filing System

Invoicing System

Payroll System

DBMSCentral database

Contains employee,order, inventory,

pricing, and customer data


Advantages of the Database Advantages of the Database ApproachApproach

Program-data independenceProgram-data independence Planned data redundancyPlanned data redundancy Improved data consistencyImproved data consistency Improved data sharingImproved data sharing Increased application development Increased application development

productivityproductivity Enforcement of standardsEnforcement of standards Improved data qualityImproved data quality Improved data accessibility and Improved data accessibility and

responsivenessresponsiveness Reduced program maintenanceReduced program maintenance Improved decision supportImproved decision support


Costs and Risks of the Database Costs and Risks of the Database ApproachApproach

New, specialized personnelNew, specialized personnel Installation and management cost Installation and management cost

and complexityand complexity Conversion costsConversion costs Need for explicit backup and Need for explicit backup and

recoveryrecovery Organizational conflictOrganizational conflict


Elements of the Database Elements of the Database ApproachApproach

Data models Data models Graphical system capturing nature and relationship of dataGraphical system capturing nature and relationship of data Enterprise Data Model–high-level entities and relationships Enterprise Data Model–high-level entities and relationships

for the organizationfor the organization Project Data Model–more detailed view, matching data Project Data Model–more detailed view, matching data

structure in database or data warehouse structure in database or data warehouse Relational DatabasesRelational Databases

Database technology involving tables (relations) Database technology involving tables (relations) representing entities and primary/foreign keys representing entities and primary/foreign keys representing relationshipsrepresenting relationships

Use of Internet TechnologyUse of Internet Technology Networks and telecommunications, distributed databases, Networks and telecommunications, distributed databases,

client-server, and 3-tier architecturesclient-server, and 3-tier architectures Database ApplicationsDatabase Applications

Application programs used to perform database activities Application programs used to perform database activities (create, read, update, and delete) for database users(create, read, update, and delete) for database users


Segment of an Enterprise Data Model

Segment of a Project-Level Data Model


One customer may place many orders, but each order is placed by a single customer

One-to-many relationship


One order has many order lines; each order line is associated with a single order



One product can be in many order lines, each order line refers to a single product



Therefore, one order involves many products and one product is involved in many orders

Many-to-many relationship


Figure 1-4 Enterprise data model for Figure 1-3 segments


Figure 1-5 Components of the Database Environment


Components of the Components of the Database EnvironmentDatabase Environment

CASE ToolsCASE Tools––computer-aided software engineeringcomputer-aided software engineering RepositoryRepository––centralized storehouse of metadatacentralized storehouse of metadata Database Management System (DBMS) Database Management System (DBMS) ––

software for managing the databasesoftware for managing the database DatabaseDatabase––storehouse of the datastorehouse of the data Application ProgramsApplication Programs––software using the datasoftware using the data User InterfaceUser Interface––text and graphical displays to text and graphical displays to

usersusers Data/Database AdministratorsData/Database Administrators––personnel personnel

responsible for maintaining the databaseresponsible for maintaining the database System DevelopersSystem Developers––personnel responsible for personnel responsible for

designing databases and softwaredesigning databases and software End UsersEnd Users––people who use the applications and people who use the applications and

databasesdatabases


The Range of Database The Range of Database ApplicationsApplications

Personal databasesPersonal databases Workgroup databasesWorkgroup databases Departmental/divisional databasesDepartmental/divisional databases Enterprise databaseEnterprise database


Figure 1-6Typical data from a personal database


Figure 1-7 Workgroup database with wireless local area network


Enterprise Database Enterprise Database ApplicationsApplications

Enterprise Resource Planning (ERP)Enterprise Resource Planning (ERP) Integrate all enterprise functions Integrate all enterprise functions

(manufacturing, finance, sales, marketing, (manufacturing, finance, sales, marketing, inventory, accounting, human resources)inventory, accounting, human resources)

Data WarehouseData Warehouse Integrated decision support system derived Integrated decision support system derived

from various operational databasesfrom various operational databases


Figure 1-8 An enterprise data warehouse


Evolution of DB SystemsEvolution of DB Systems

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