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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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sdlc phases
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

chapter 10
Chapter 10

Application Development

Systems Analysis and Design Fourth Edition

objectives
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

objectives5
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

objectives6
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

objectives7
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

introduction
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

quality assurance
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

quality assurance10
Quality Assurance
  • Software engineering
    • Stresses quality in software design
      • Solid design
      • Effective structure
      • Accurate documentation
      • Careful testing

Systems Analysis and Design Fourth Edition

quality assurance11
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

quality assurance12
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

overview of application development
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

overview of application development14
Overview of ApplicationDevelopment

Systems Analysis and Design Fourth Edition

overview of application development15
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

structured application development
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

structured application development17
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

structured application development18
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

structured application development19
Structured Application Development
  • Structure chart examples

Systems Analysis and Design Fourth Edition

structured application development20
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

other application development tools
Other Application DevelopmentTools
  • Program flowcharts
    • Graphically represent the logic and interaction between program modules

Systems Analysis and Design Fourth Edition

other application development tools22
Other Application DevelopmentTools
  • Pseudocode
    • A technique for representing program logic
    • Is not language specific

Systems Analysis and Design Fourth Edition

coding
Coding
  • Process of turning program logic into specific instructions that can be executed by the computer system

Systems Analysis and Design Fourth Edition

testing the application
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

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testing the application25
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

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testing the application26
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

testing the application27
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

documentation
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

documentation29
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

documentation30
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

documentation31
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

documentation32
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

documentation33
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

management approval
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