Chap 01 Corrected

2007 by Prentice Hall*Chapter 1:The Database EnvironmentModern Database Management8th EditionJeffrey A. Hoffer, Mary B. Prescott, Fred R. McFadden

2007 by Prentice Hall

Chapter 1 2007 by Prentice Hall

*ObjectivesDefinition of termsExplain growth and importance of databasesName limitations of conventional file processingIdentify five categories of databasesExplain advantages of databasesIdentify costs and risks of databasesList components of database environmentDescribe evolution of database systems


*DefinitionsDatabase: organized collection of logically related dataData: stored representations of meaningful objects and eventsStructured: numbers, text, datesUnstructured: images, video, documentsInformation: data processed to increase knowledge in the person using the dataMetadata: data that describes the properties and context of user data


*Figure 1-1a Data in contextContext helps users understand data


*Graphical displays turn data into useful information that managers can use for decision making and interpretationFigure 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 ProcessingProgram-Data DependenceAll programs maintain metadata for each file they useDuplication of DataDifferent systems/programs have separate copies of the same dataLimited Data SharingNo centralized control of dataLengthy Development TimesProgrammers must design their own file formatsExcessive Program Maintenance80% of information systems budget


*Problems with Data DependencyEach application programmer must maintain his/her own dataEach application program needs to include code for the metadata of each fileEach application program must have its own processing routines for reading, inserting, updating, and deleting dataLack of coordination and central controlNon-standard file formats


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


*Problems with Data RedundancyWaste of space to have duplicate dataCauses more maintenance headachesThe biggest problem: Data changes in one file could cause inconsistenciesCompromises in data integrity


*SOLUTION: The DATABASE ApproachCentral repository of shared dataData is managed by a controlling agentStored in a standardized, convenient form

Requires a Database Management System (DBMS)


*Database Management SystemDBMS manages data resources like an operating system manages hardware resourcesA software system that is used to create, maintain, and provide controlled access to user databases

Order Filing SystemInvoicing SystemPayroll SystemDBMS

Central database

Contains employee,order, inventory, pricing, and customer data


*Advantages of the Database ApproachProgram-data independencePlanned data redundancyImproved data consistencyImproved data sharingIncreased application development productivityEnforcement of standardsImproved data qualityImproved data accessibility and responsivenessReduced program maintenanceImproved decision support


*Costs and Risks of the Database ApproachNew, specialized personnelInstallation and management cost and complexityConversion costsNeed for explicit backup and recoveryOrganizational conflict


*Elements of the Database ApproachData models Graphical system capturing nature and relationship of dataEnterprise Data Modelhigh-level entities and relationships for the organizationProject Data Modelmore detailed view, matching data structure in database or data warehouse Relational DatabasesDatabase technology involving tables (relations) representing entities and primary/foreign keys representing relationshipsUse of Internet TechnologyNetworks and telecommunications, distributed databases, client-server, and 3-tier architecturesDatabase ApplicationsApplication programs used to perform database activities (create, read, update, and delete) for database users


*Segment of an Enterprise Data ModelSegment 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-to-many relationship


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


*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 Database EnvironmentCASE Toolscomputer-aided software engineeringRepositorycentralized storehouse of metadataDatabase Management System (DBMS) software for managing the databaseDatabasestorehouse of the dataApplication Programssoftware using the dataUser Interfacetext and graphical displays to usersData/Database Administratorspersonnel responsible for maintaining the databaseSystem Developerspersonnel responsible for designing databases and softwareEnd Userspeople who use the applications and databases


*The Range of Database ApplicationsPersonal databasesWorkgroup databasesDepartmental/divisional databasesEnterprise database


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*Figure 1-6Typical data from a personal database


*Figure 1-7 Workgroup database with wireless local area network


*Enterprise Database ApplicationsEnterprise Resource Planning (ERP)Integrate all enterprise functions (manufacturing, finance, sales, marketing, inventory, accounting, human resources)Data WarehouseIntegrated decision support system derived from various operational databases


*Figure 1-8 An enterprise data warehouse


*Evolution of DB Systems


Kang Yayan (SAP)Komputer teknologiErpweaver

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Chap 01 Corrected

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