© 2011 Pearson Education, Inc. Publishing as Prentice Hall 1 Chapter 1: The Database Environment...

© 2011 Pearson Education, Inc. Publishing as © 2011 Pearson Education, Inc. Publishing as Prentice HallPrentice Hall 11

Chapter 1:Chapter 1:The Database The Database

Environment and Environment and Development ProcessDevelopment Process

Modern Database Modern Database ManagementManagement

1010thth Edition EditionJeffrey A. Hoffer, V. Ramesh, Jeffrey A. Hoffer, V. Ramesh,

Heikki TopiHeikki Topi

Chapter 1 © 2011 Pearson Education, Inc. Publishing as Prentice Hall© 2011 Pearson Education, Inc. Publishing as Prentice Hall 22

ObjectivesObjectives Define termsDefine terms Name limitations of conventional file processingName limitations of conventional file processing 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 Identify categories of database applicationsIdentify categories of database applications Describe database system development life cycleDescribe database system development life cycle Explain prototyping and agile development approachesExplain prototyping and agile development approaches Explain roles of individualsExplain roles of individuals Explain the three-schema architecture for databasesExplain the three-schema architecture for databases


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

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99

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 EntitiesEntities

Noun form describing a person, place, object, event, or Noun form describing a person, place, object, event, or conceptconcept

Composed of attributesComposed of attributes RelationshipsRelationships

Between entitiesBetween entities Usually one-to-many (1:M) or many-to-many (M:N)Usually one-to-many (1:M) or many-to-many (M:N)

Relational DatabasesRelational Databases Database technology involving tables (relations) representing Database technology involving tables (relations) representing

entities and primary/foreign keys representing relationshipsentities and primary/foreign keys representing relationships


Segment of an enterprise data model

Segment of a project-level data model

Figure 1-3 Comparison of enterprise and project level data models


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 1-5 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 Two-tier Client/Server databasesTwo-tier Client/Server databases Multitier Client/Server databasesMultitier Client/Server databases Enterprise applicationsEnterprise applications

Enterprise resource planning (ERP) Enterprise resource planning (ERP) systemssystems

Data warehousing implementationsData warehousing implementations


Figure 1-6 Two-tier database with localarea network


Figure 1-7 Three-tiered client/server database architecture


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 1-8a Evolution of database technologies


Enterprise Data ModelEnterprise Data Model

First step in database developmentFirst step in database development Specifies scope and general contentSpecifies scope and general content Overall picture of organizational data at Overall picture of organizational data at

high level of abstractionhigh level of abstraction Entity-relationship diagramEntity-relationship diagram Descriptions of entity typesDescriptions of entity types Relationships between entitiesRelationships between entities Business rulesBusiness rules


FIGURE 1-9 Example business function-to-data entity matrix


Two Approaches to Two Approaches to Database and IS Database and IS

DevelopmentDevelopment SDLCSDLC System Development Life CycleSystem Development Life Cycle Detailed, well-planned development processDetailed, well-planned development process Time-consuming, but comprehensiveTime-consuming, but comprehensive Long development cycleLong development cycle

PrototypingPrototyping Rapid application development (RAD)Rapid application development (RAD) Cursory attempt at conceptual data modelingCursory attempt at conceptual data modeling Define database during development of initial prototypeDefine database during development of initial prototype Repeat implementation and maintenance activities with Repeat implementation and maintenance activities with

new prototype versionsnew prototype versions


Systems Development Life CycleSystems Development Life Cycle(see also Figure 1-10) (see also Figure 1-10)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design


Systems Development Life CycleSystems Development Life Cycle(see also Figure 1-10) (cont.)(see also Figure 1-10) (cont.)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Planning Purpose––preliminary understandingDeliverable––request for study

Database activity–– enterprise modeling and early conceptual data modeling


Systems Development Life CycleSystems Development Life Cycle(see also Figure 1-10) (cont.) (see also Figure 1-10) (cont.)

Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Analysis

Purpose–thorough requirements analysis and structuring

Deliverable–functional system specifications

Database activity–thorough and integrated conceptual data modeling



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical DesignLogical Design

Purpose–information requirements elicitation and structure

Deliverable–detailed design specifications

Database activity– logical database design (transactions, forms, displays, views, data

integrity and security)



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Physical Design

Purpose–develop technology and organizational specifications

Deliverable–program/data structures, technology purchases, organization redesigns

Database activity– physical database design (define database to DBMS, physical data organization, database processing programs)



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Implementation

Purpose–programming, testing, training, installation, documenting

Deliverable–operational programs, documentation, training materials

Database activity– database implementation, including coded programs, documentation, installation and conversion



Planning

Analysis

Physical Design

Implementation

Maintenance

Logical Design

Maintenance

Purpose–monitor, repair, enhance

Deliverable–periodic audits

Database activity– database maintenance,

performance analysis and tuning, error

corrections


Prototyping Database Prototyping Database MethodologyMethodology(Figure 1-11) (Figure 1-11)


Prototyping Database Prototyping Database MethodologyMethodology

(Figure 1-11) (Figure 1-11) (cont.)(cont.)



(Figure 1-11)(Figure 1-11) (cont.) (cont.)



(Figure 1-11) (Figure 1-11) (cont.)(cont.)


Database SchemaDatabase Schema External SchemaExternal Schema

User ViewsUser Views Subsets of Conceptual SchemaSubsets of Conceptual Schema Can be determined from business-function/data Can be determined from business-function/data

entity matricesentity matrices DBA determines schema for different usersDBA determines schema for different users

Conceptual SchemaConceptual Schema E-R models–covered in Chapters 2 and 3E-R models–covered in Chapters 2 and 3

Internal Schema Internal Schema Logical structures–covered in Chapter 4Logical structures–covered in Chapter 4 Physical structures–covered in Chapter 5Physical structures–covered in Chapter 5


Different people have different

views of the database…these are the external

schema

The internal schema is the

underlying design and

implementation

Figure 1-12 Three-schema architecture


Managing ProjectsManaging Projects Project–a planned undertaking of related Project–a planned undertaking of related

activities to reach an objective that has a activities to reach an objective that has a beginning and an endbeginning and an end

Involves use of review points for:Involves use of review points for: Validation of satisfactory progressValidation of satisfactory progress Step back from detail to overall viewStep back from detail to overall view Renew commitment of stakeholdersRenew commitment of stakeholders

Incremental commitment–review of systems Incremental commitment–review of systems development project after each development development project after each development phase with rejustification after each phasephase with rejustification after each phase


Managing Projects: People Managing Projects: People InvolvedInvolved

Business analystsBusiness analysts Systems analystsSystems analysts Database analysts and data modelersDatabase analysts and data modelers UsersUsers ProgrammersProgrammers Database architectsDatabase architects Data administratorsData administrators Project managersProject managers Other technical expertsOther technical experts


FIGURE 1-13 ComputerSystem for Pine ValleyFurniture Company


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© 2011 Pearson Education, Inc. Publishing as Prentice Hall 1 Chapter 1: The Database Environment...

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