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Systems Implementation

Application Development. Systems Implementation. SDLC Phases. Phase 4: Systems Implementation Objectives Learn about application development, including designing, writing, testing, and documenting programs and code modules

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Systems Implementation

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  1. Application Development Systems Implementation

  2. SDLC Phases Phase 4: Systems Implementation Objectives • Learn about application development, including designing, writing, testing, and documenting programs and code modules • Perform installation and evaluation tasks, including user training, file conversion, system changeover, and evaluation of the results Systems Analysis and Design Fourth Edition

  3. Chapter 10 Application Development Systems Analysis and Design Fourth Edition

  4. Objectives • Describe the major tasks and activitiesthat are completed during the systems implementation phase • Discuss the role of the systems analyst during application development • Explain the importance of quality assurance and the role of software engineering in software development Systems Analysis and Design Fourth Edition

  5. Objectives • Describe top-down and modular design • Explain cohesion and coupling, and draw a structure chart that illustrates the concepts • Explain how you can use program flowcharts and pseudocode to document program logic Systems Analysis and Design Fourth Edition

  6. Objectives • Describe the coding process and explain how program code is generated • Explain object-oriented application development and list the advantages of this approach • Explain testing phases, including unit testing, integration testing, and system testing Systems Analysis and Design Fourth Edition

  7. Objectives • Describe the types of documentation a systems analyst must prepare • Explain the importance of management approval at this stage of systems development, and describe the information that systems analysts must provide to management Systems Analysis and Design Fourth Edition

  8. Introduction • During the systems implementation phase, the development team uses the system design specification as a blueprint for constructing the new system • Analysts and programmers have different roles during application development • An analyst's main task is to deliver clear, accurate specifications to a programmer Systems Analysis and Design Fourth Edition

  9. Quality Assurance • Quality assurance is vitally important in all business areas, including IT functions • The main objective of quality assurance is to detect and avoid problems as early as possible • Quality assurance can detect • Inaccurate requirements • Design or coding errors • Faulty documentation • Ineffective testing Systems Analysis and Design Fourth Edition

  10. Quality Assurance • Software engineering • Stresses quality in software design • Solid design • Effective structure • Accurate documentation • Careful testing Systems Analysis and Design Fourth Edition

  11. Quality Assurance • Software engineering • Stresses quality in software design • Solid design • Effective structure • Accurate documentation • Careful testing • Software Engineering Institute (SEI) • Mission is to improve quality of software-based systems • Capability Maturity Model is designed to improve quality, reduce development time, and cut costs Systems Analysis and Design Fourth Edition

  12. Quality Assurance • International Organization for Standardization (ISO) • Seeks to offer global consensus of what constitutes good management practices • ISO 9000-3 provides a quality assurance framework for developing and maintaining software Systems Analysis and Design Fourth Edition

  13. Overview of ApplicationDevelopment • Planning the overall design strategy • Use top-down (modular) approach and partition the system into subsystems and modules • Develop programs and modules • Design, code, test, and document • Test the system • Link test • System test • Complete all documentation Systems Analysis and Design Fourth Edition

  14. Overview of ApplicationDevelopment Systems Analysis and Design Fourth Edition

  15. Overview of ApplicationDevelopment • Documentation review • Program designs are based on • System design specification • DFDs • Process descriptions • Object models • Class diagrams • ERDs • Screen layouts • Report layouts • Source documents • Data dictionary entries Systems Analysis and Design Fourth Edition

  16. Structured Application Development • A programmer creates modules that perform specific tasks or functions • A module consists of related program code organized into small units that are easy to understand and maintain • Most analysts use a top-down approach when planning a system Systems Analysis and Design Fourth Edition

  17. Structured Application Development • Structure charts • Show the relationships among program modules • Chart symbols represent • Modules • Data couples • Control couples • Conditions • Loops Systems Analysis and Design Fourth Edition

  18. Structured Application Development • Cohesion and coupling • Cohesion measures a module’s scope and processing characteristics • A module that performs a single function has a high degree of cohesion • Coupling measures relationships and interdependence among modules • Modules that are relatively independent are loosely coupled • If one module refers to internal logic contained in another module, those modules are tightly coupled Systems Analysis and Design Fourth Edition

  19. Structured Application Development • Structure chart examples Systems Analysis and Design Fourth Edition

  20. Structured Application Development • Steps in drawing a structure chart • Review the DFDs and object models • Identify modules and relationships • Add couples, loops, and conditions • Analyze the structure chart, the DFDs, and the data dictionary Systems Analysis and Design Fourth Edition

  21. Other Application DevelopmentTools • Program flowcharts • Graphically represent the logic and interaction between program modules Systems Analysis and Design Fourth Edition

  22. Other Application DevelopmentTools • Pseudocode • A technique for representing program logic • Is not language specific Systems Analysis and Design Fourth Edition

  23. Coding • Process of turning program logic into specific instructions that can be executed by the computer system Systems Analysis and Design Fourth Edition

  24. Testing the Application • Testing is necessary to ensure that all programs function correctly • First step is to detect syntax errors and obtain a clean compilation • Next step is to eliminate logic errors • Techniques include desk checking, structured walkthrough, and code review • Final step is testing • Unit, integration, and systems testing Systems Analysis and Design Fourth Edition

  25. Testing the Application • Unit testing • Involves an individual program • Objective is to identify and eliminate execution errors and any remaining logic errors • Stub testing is a technique of using stubs to represent entry or exit points that will be linked later to another program or data file Systems Analysis and Design Fourth Edition

  26. Testing the Application • Integration testing • Involves two or more programs that depend on each other • Also link testing • Integration testing ensures that the job streams are correct • Test data is necessary to simulate actual conditions and test the interface between programs Systems Analysis and Design Fourth Edition

  27. Testing the Application • System testing • Involves the entire information system and includes all typical processing situations • Requires users to verify all processing options and outputs • Uses live data • Involves a final test of all programs • Ensures that proper documentation is ready • Verifies that all system components work correctly • Confirms that the system can handle predicted data volumes in a timely and efficient manner Systems Analysis and Design Fourth Edition

  28. Documentation • Explains the system and helps peopleinteract with it • Types of documentation • Program documentation • System documentation • Operations documentation • User documentation Systems Analysis and Design Fourth Edition

  29. Documentation • Program documentation • Begins in the systems analysis phase and continues during systems implementation • Includes process descriptions and report layouts • Programmers provide documentation with comments that make it easier to understand and maintain the program • An analyst must verify that program documentation is accurate and complete Systems Analysis and Design Fourth Edition

  30. Documentation • System documentation • System documentation describes the system’s functions and how they are implemented • Most system documentation is prepared during the systems analysis and systems design phases • Documentation consists of • Data dictionary entries • Data flow diagrams • Object models • Screen layouts • Source documents • Initial systems request Systems Analysis and Design Fourth Edition

  31. Documentation • Operations documentation • Typically used in a minicomputer or mainframe environment with centralized processing and batch job scheduling • Documentation tells the IT operations group how and when to run programs • Common example is a program run sheet, which contains information needed for processing and distributing output Systems Analysis and Design Fourth Edition

  32. Documentation • User documentation • Typically includes the following items • System overview • Source document description, with samples • Menu and data entry screens • Reports that are available, with samples • Security and audit trail information • Responsibility for input, output, processing • Procedures for handling changes/problems • Examples of exceptions and error situations • Frequently asked questions (FAQ) • Explanation of Help & updating the manual Systems Analysis and Design Fourth Edition

  33. Documentation • User documentation • Online documentation can empower users and reduce the need for direct IT support • Context-sensitive Help • Interactive tutorials • Hints and tips • Hypertext • Interactive tutorials • Written documentation material often is provided in a user manual • Analysts prepare the material and users review it and participate in developing the manual Systems Analysis and Design Fourth Edition

  34. Management Approval • After system testing is complete, the results are presented to management • Test results • Status of all required documentation • Input from users who participated • Detailed time schedules, cost estimates, and staffing requirements • If approved, a schedule for system installation and evaluation will be established Systems Analysis and Design Fourth Edition

  35. EndChapter 10

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