© 2011 pearson education, inc. publishing as prentice hall 1 chapter 1: the database environment...
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© 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
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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
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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
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Figure 1-1a Data in context
Context helps users understand data
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Graphical displays turn data into useful information that managers can use for decision making and
interpretation
Figure 1-1b Summarized data
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Descriptions of the properties or characteristics of the data, including data types, field sizes, allowable values, and
data context
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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
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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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Duplicate Data
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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
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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)
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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
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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
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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
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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
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Segment of an enterprise data model
Segment of a project-level data model
Figure 1-3 Comparison of enterprise and project level data models
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One customer may place many orders, but each order is placed by a single customer
One-to-many relationship
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One order has many order lines; each order line is associated with a single order
One-to-many relationship
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One product can be in many order lines, each order line refers to a single product
One-to-many relationship
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Therefore, one order involves many products and one product is involved in many orders
Many-to-many relationship
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Figure 1-5 Components of the Database Environment
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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
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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
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Figure 1-6 Two-tier database with localarea network
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Figure 1-7 Three-tiered client/server database architecture
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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
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Figure 1-8a Evolution of database technologies
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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
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FIGURE 1-9 Example business function-to-data entity matrix
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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
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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
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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
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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
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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 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)
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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
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)
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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
Implementation
Purpose–programming, testing, training, installation, documenting
Deliverable–operational programs, documentation, training materials
Database activity– database implementation, including coded programs, documentation, installation and conversion
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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
Maintenance
Purpose–monitor, repair, enhance
Deliverable–periodic audits
Database activity– database maintenance,
performance analysis and tuning, error
corrections
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Prototyping Database Prototyping Database MethodologyMethodology(Figure 1-11) (Figure 1-11)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 1-11) (Figure 1-11) (cont.)(cont.)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 1-11)(Figure 1-11) (cont.) (cont.)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 1-11)(Figure 1-11) (cont.) (cont.)
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Prototyping Database Prototyping Database MethodologyMethodology
(Figure 1-11) (Figure 1-11) (cont.)(cont.)
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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
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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
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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
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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
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FIGURE 1-13 ComputerSystem for Pine ValleyFurniture Company
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