Bài giảng Systems Analysis and Design - Chapter 2: Understanding Organizational Style and Its Impact on Information Systems

Understanding Organizational Style and Its Impact on Information SystemsSystems Analysis and Design, 7eKendall & Kendall2©2008 Pearson Prentice HallKendall & Kendall2-*Learning ObjectivesUnderstand that organizations and their members are systems and that analysts need to take a systems perspectiveDepict systems graphically using context-level data flow diagrams, and entity-relationship models, use cases and use case scenariosRecognize that different levels of management require different systemsComprehend that organizational culture impacts the design of information systems Kendall & Kendall2-*Three Main Forces Interacting to Shape OrganizationsLevels of managementDesign of organizationsOrganizational culturesKendall & Kendall2-*Organizations Are Composed of Interrelated SubsystemsInfluenced by levels of management decision makers that cut horizontally across the organizational systemOperationsMiddle managementStrategic managementInfluenced by organizational cultures and subculturesKendall & Kendall2-*Major TopicsOrganizations as systemsDepicting systems graphicallyData flow diagramEntity-relationship modelUse case modelingLevels of managementOrganizational cultureKendall & Kendall2-*Organizations As SystemsConceptualized as systems designed to accomplish predetermined goals and objectivesComposed of smaller, interrelated systems serving specialized functionsSpecialized functions are reintegrated to form an effective organizational wholeKendall & Kendall2-*Interrelatedness and Independence of SystemsAll systems and subsystems are interrelated and interdependentAll systems process inputs from their environmentsAll systems are contained by boundaries separating them from their environmentsSystem feedback for planning and controlAn ideal system self-corrects or self-regulates itself Kendall & Kendall2-*Figure 2.1 System outputs serve as feedback that compares performance with goalsKendall & Kendall2-*Organizational EnvironmentsCommunityPhysical locationDemographic profile (education, income)EconomicMarket factorsCompetitionPolitical State and local governmentKendall & Kendall2-*Openness and ClosednessOpenFree flow of informationOutput from one system becomes input to anotherClosedRestricted access to informationLimited by numerous rulesInformation only on a “need to know” basisKendall & Kendall2-*Virtual Organizations and Virtual TeamsA virtual organization has parts of the organization in different physical locationsComputer networks and communications technology are used to bring virtual teams together to work on projectsKendall & Kendall2-*Benefits of Virtual Organizations and TeamsPossibility of reducing costs of physical facilitiesMore rapid response to customer needsHelping virtual employees to fulfill their familial obligations to children or aging parentsKendall & Kendall2-*Taking a Systems PerspectiveAllows system analyst to understand businesses before they begin their tasks It is important that members of subsystems realize that they are interrelated with other subsystems Problems occur when each manager thinks that his/her department is the most important Bigger problems may occur when that manager rises through the ranks Kendall & Kendall2-*Taking a Systems PerspectiveKendall & Kendall2-*Taking a Systems PerspectiveKendall & Kendall2-*Enterprise Resource PlanningEnterprise Resource Planning (ERP) describes an integrated organizational information systemSoftware that helps the flow of information between the functional areas within the organizationKendall & Kendall2-*Depicting Systems GraphicallyContext-level data flow diagramsEntity-relationship modelUse Case ModelingKendall & Kendall2-*Context-Level Data Flow DiagramsFocus is on the data flowing into and out of the system and the processing of the dataKendall & Kendall2-*Figure 2.4 The basic symbols of a data flow diagramKendall & Kendall2-*Airline Reservation SystemKendall & Kendall2-*Entity-Relationship ModelFocus is on the entities and their relationships within the organizational systemKendall & Kendall2-*RelationshipsRelationships show how the entities are connectedThree types of relationshipsOne-to-oneOne-to-manyMany-to-manyKendall & Kendall2-*Entity-Relationship ExampleKendall & Kendall2-*Figure 2.8 Examples of different types of relationships in E-R diagramsKendall & Kendall2-*EntitiesFundamental entityAssociative entityAttributive entityKendall & Kendall2-*Figure 2.9 Three different types of entities used in E-R diagramsKendall & Kendall2-*AttributesData attributes may be added to the diagramKendall & Kendall2-*Creating Entity-Relationship DiagramsList the entities in the organizationChoose key entities to narrow the scope of the problemIdentify what the primary entity should beConfirm the results of the above through data gatheringKendall & Kendall2-*Figure 2-12 A more complete E-R diagram showing data attributes of the entities Kendall & Kendall2-*Use Case ModelingDescribes what a system does without describing how the system does it; that is, it is a logical model of the systemKendall & Kendall2-*Use Case DiagramActorRefers to a particular role of a user of the systemSimilar to external entities; they exist outside of the systemUse case symbolsAn oval indicating the task of the use caseConnecting linesArrows and lines used to diagram behavioral relationshipsKendall & Kendall2-*ActorDivided into two groupsPrimary actorsSupply data or receive information from the systemProvide details on what the use case should doSupporting actorsHelp to keep the system running or provide helpThe people who run the help desk, the analysts, programmers, and so onKendall & Kendall2-*A Use Case Always Provides Three ThingsAn actor that initiates an eventThe event that triggers a use caseThe use case that performs the actions triggered by the eventKendall & Kendall2-*Use Case RelationsBehavioral relationshipsCommunicatesUsed to connect an actor to a use caseIncludesDescribes the situation in which a use case contains behavior that is common to more than one use caseKendall & Kendall2-*Use Case RelationsBehavioral relationships (Continued) ExtendsDescribes the situation in which one use case possesses the behavior that allows the new case to handle a variation or exception from the basic use caseGeneralizesImplies that one thing is more typical than the other thingKendall & Kendall2-*Figure 2.13 Some components of use case diagrams showing actors, use cases, and relationships for a student enrollment exampleKendall & Kendall2-*Figure 2.14 Examples of use cases and behavioral relationships for student enrollmentKendall & Kendall2-*Developing Use Case DiagramsReview the business specifications and identify the actors involvedIdentify the high-level events and develop the primary use cases that describe those events and how the actors initiate themReview each primary use case to determine the possible variations of flow through the use caseThe context-level data flow diagram could act as a starting point for creating a use caseKendall & Kendall2-*Figure 2.15 A use case diagram representing a system used to plan a conferenceKendall & Kendall2-*Developing the Use Case ScenariosThe description of the use caseThree main areasUse case identifiers and initiatorsSteps performedConditions, assumptions, and questionsKendall & Kendall2-*Figure 2.16 A use case scenario is divided into three sections: identification and initiation; steps performed; and conditions, assumptions, and questionsKendall & Kendall2-*Why Use Case Diagrams Are HelpfulIdentify all the actors in the problem domainActions that need to be completed are also clearly shown on the use case diagramThe use case scenario is also worthwhileSimplicity and lack of technical detailKendall & Kendall2-*Figure 2.17 The main reasons for writing use cases are their effectiveness in communicating with users and their capturing of user storiesKendall & Kendall2-*Figure 2.18 Management in organizations exists on three horizontal levels: operational control, managerial planning and control, and strategic managementKendall & Kendall2-*Operations ControlMake decisions using predetermined rules that have predictable outcomes Oversee the operating details of the organizationKendall & Kendall2-*Managerial Planning and ControlMake short-term planning and control decisions about resources and organizational objectivesDecisions may be partly operational and partly strategicKendall & Kendall2-*Strategic ManagementLook outward from the organization to the futureMake decisions that will guide middle and operations managersWork in highly uncertain decision-making environmentDefine the organization as a wholeKendall & Kendall2-*Managerial LevelsDifferent organization structureLeadership styleTechnological considerationsOrganization cultureHuman interactionAll carry implications for the analysis and design of information systemsKendall & Kendall2-*Organizational CultureOrganizations have cultures and subculturesLearn from verbal and nonverbal symbolismKendall & Kendall2-*Verbal SymbolismMythsMetaphorsVisionsHumorKendall & Kendall2-*Nonverbal SymbolismShared artifactsTrophies, etc.Rites and ritualsPromotionsBirthdays, etc.Clothing wornOffice placement and decorationsKendall & Kendall2-*SummaryOrganizational fundamentalsOrganizations as systemsLevels of managementOrganizational cultureGraphical representation of systemsDFDERDUse case diagrams and scenariosKendall & Kendall2-*Summary (Continued)Levels of managerial controlOperationalMiddle managementStrategicOrganizational culture