Bài giảng Business Driven Technology - Business plug-in B14 - Systems Development

BUSINESS PLUG-IN B14Systems DevelopmentLEARNING OUTCOMESSummarize the activities associated with the planning phase in the SDLCSummarize the activities associated with the analysis phase in the SDLCSummarize the activities associated with the design phase in the SDLCSummarize the activities associated with the development phase in the SDLCLEARNING OUTCOMESSummarize the activities associated with the testing phase in the SDLCSummarize the activities associated with the implementation phase in the SDLCSummarize the activities associated with the maintenance phase in the SDLCIntroductionLarge, complex IT systems take teams of architects, analysts, developers, testers, and users many years to createThe systems development life cycle is the foundation for many systems development methodologies such as RAD and agileSystems development life cycle – the overall process for developing information systems from planning and analysis through implementation and maintenanceIntroductionSystems Development Life Cycle - PHASE 1: PLANNINGPlanning phase – involves establishing a high-level plan of the intended project and determining project goalsPrimary planning activities includeIdentify and select the system for developmentAssess project feasibilityDevelop the project planPLANNING 1: Identify and Select the System for DevelopmentOrganizations use different forms of evaluation criteria to determine which systems to develop Critical success factor (CSF) – a factor that is critical to an organization’s successPLANNING 1: Identify and Select the System for DevelopmentPLANNING 2: Assess Project FeasibilityFeasibility study – determines if the proposed solution is feasible and achievable from a financial, technical, and organizational standpointDifferent types of feasibility studiesEconomic feasibility studyOperational feasibility studyTechnical feasibility studySchedule feasibility studyLegal and contractual feasibility studyPLANNING 3: Develop the Project PlanDeveloping the project plan is a difficult and important activityThe project plan is the guiding force behind on-time delivery of a complete and successful systemContinuous updating of the project plan must be performed during every subsequent phase during the SDLCSystems Development Life Cycle – PHASE 2: ANALYSISAnalysis phase – involves analyzing end-user business requirements and refining project goals into defined functions and operations of the intended systemPrimary analysis activities include:Gather business requirementsCreate process diagramsPerform a buy vs. build analysisANALYSIS 1: Gather Business RequirementsBusiness requirements – the detailed set of business requests that the system must meet in order to be successfulDifferent ways to gather business requirementsJoint application development (JAD) session – where employees meet to define or review the business requirements for the systemInterviewsQuestionnairesObservationsReview business documentsANALYSIS 1: Gather Business RequirementsThe system users review the requirements definition document and determine if they will sign-off on the business requirementsRequirements definition document – contains the final set of business requirements, prioritized in order of business importanceSign-off – the system users’ actual signatures indicating they approve all of the business requirementsANALYSIS 2: Create Process DiagramsProcess modeling – graphically representing the processes that capture, manipulate, store, and distribute information between a system and its environmentCommon process modeling diagrams includeData flow diagram (DFD) – illustrates the movement of information between external entities and the processes and data stores within the systemComputer-aided software engineering (CASE) tools –automate systems analysis, design, and developmentANALYSIS 2: Create Process DiagramsSample data flow diagramANALYSIS 3: Perform a Buy vs. Build AnalysisAn organization faces two primary choices when deciding to develop an information systemBuy the information system from a vendorCommercial off-the shelf (COTS) – software package or solution that is purchased to support one or more business functions and information systemsSCM, CRM, and ERP solutions are typically COTSBuild the information system itselfANALYSIS 3: Perform a Buy vs. Build AnalysisOrganizations must consider the following when making a buy vs. build decision:Are there any currently available products that fit the needs?Are there features that are not available and important enough to warrant the expense of in-house development?Can the organization customize or modify an existing COTS to fit its needs?Is there a justification to purchase or develop based on the acquisition cost?ANALYSIS 3: Perform a Buy vs. Build AnalysisThree key factors an organization should also consider when contemplating the buy vs. build decisionTime to marketAvailability of corporate resourcesCorporate core competenciesSystems Development Life Cycle – PHASE 3: DESIGNDesign phase – involves describing the desired features and operations of the system including screen layouts, business rules, process diagrams, pseudo code, and other documentationPrimary design activities include:Design the IT infrastructureDesign system modelsDESIGN 1: Design the IT InfrastructureSample IT infrastructureDESIGN 2: Design System ModelsModeling – the activity of drawing a graphical representation of a designDifferent modeling types include:Graphical user interface (GUI) GUI screen designData modelEntity relationship diagram (ERD)DESIGN 2: Design System ModelsSample entity relationship diagram (ERD)Systems Development Life Cycle – PHASE 4: DEVELOPMENTDevelopment phase – involves taking all of the detailed design documents from the design phase and transforming them into the actual systemPrimary development activities include:Develop the IT infrastructureDevelop the database and programsSystems Development Life Cycle – PHASE 5: TESTINGTesting phase – involves bringing all the project pieces together into a special testing environment to test for errors, bugs, and interoperability, in order to verify that the system meets all the business requirements defined in the analysis phasePrimary testing activities include:Write the test conditionsPerform the system testingTESTING 1: Write the Test ConditionsTest condition – the detailed steps the system must perform along with the expected results of each stepTESTING 2: Perform the System TestingDifferent types of testingUnit testing – tests each unit of code upon completionApplication (or system) testing – verifies that all units of code work togetherIntegration testing – exposes faults in the integration of software components or unitsBackup and recovery testing – tests the ability of an application to be restarted after failureDocumentation testing – verifies instruction guides are helpful and accurateUser acceptance testing (UAT) – tests if a system satisfies its acceptance criteriaSystems Development Life Cycle – PHASE 6: IMPLEMENTATION Implementation phase – involves placing the system into production so users can begin to perform actual business operations with the systemPrimary implementation activities include:Write detailed user documentationDetermine implementation methodProvide training for the system usersIMPLEMENTATION 1: Write Detailed User Documentation System users require user documentation that highlights how to use the systemUser documentation – highlights how to use the systemIMPLEMENTATION 2: Determine Implementation MethodFour primary implementation methods Parallel implementation Plunge implementation Pilot implementationPhased implementationIMPLEMENTATION 3: Provide Training for the System UsersOrganizations must provide training for system usersTwo most popular types of training include:Online training – runs over the Internet or off a CD-ROMWorkshop training – set in a classroom-type environment and led by an instructorSystems Development Life Cycle – PHASE 7: MAINTENANCEMaintenance phase – involves performing changes, corrections, additions, and upgrades to ensure the system continues to meet the business goalsPrimary maintenance activities include:Build a help desk to support the system usersPerform system maintenanceProvide an environment to support system changesMAINTENANCE 1: Build a Help Desk to Support the System Users Internal system users have a phone number for the help desk they call whenever they have issues or questions about the systemHelp desk – a group of people who respond to internal system user questionsProviding a help desk is an excellent way to provide comprehensive support for new system usersMAINTENANCE 2: Perform System MaintenanceMaintenance – fixing or enhancing an information systemDifferent types of maintenance include:Adaptive maintenance Corrective maintenance Perfective maintenance Preventative maintenanceMAINTENANCE 3: PROVIDE AN ENVIRONMENT TO SUPPORT SYSTEM CHANGESAn organization must modify its systems to support the business environmentIt typically accomplishes this through change management systems and change control boardsChange management system – a collection of procedures to document a change request and define the steps necessary to consider the change based on the expected impact of the changeChange control board (CCB) – responsible for approving or rejecting all change requestsCLOSING CASE ONEDisaster at Denver International AirportDIAs baggage system relied on 300 computers to route bags and 4,000 telecars to carry luggage across 21 miles of trackDue to baggage system failures, DIA delayed its opening for 16 months, costing taxpayers roughly $1 million per day, which totaled around $500 millionCLOSING CASE ONE QUESTIONSOne of the problems with DIA’s baggage system was inadequate testing. Describe the different types of tests DIA could have used to help ensure its baggage system’s successEvaluate the different implementation approaches. Which one would have most significantly increased the chances of the project’s success?Explain the cost of finding errors. How could more time spent in the analysis and design phase have saved Colorado taxpayers hundreds of millions of dollars?Why could BAE not take an existing IT infrastructure and simply increase its scale and expect it to work?CLOSING CASE TWOReducing Ambiguity in Business RequirementsThe number one reason projects fail is bad business requirementsBusiness requirements are considered “bad” because of ambiguity or insufficient involvement of end users during analysis and designA requirement is unambiguous if it has the same interpretation for all partiesCLOSING CASE TWO QUESTIONSWhy are ambiguous business requirements the leading cause of system development failures?Why do the words “and” and “or” tend to lead to ambiguous requirements?Research the web and determine other reasons for “bad” business requirementsWhat is wrong with the following business requirement: “The system must support employee birthdays since every employee always has a birthday every year”