1 9 moving to design lecture 4. 2 9 analysis objectives to design objectives figure 9-2

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9

Moving to Design

Lecture 4

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9Analysis Objectives to Design ObjectivesFigure 9-2

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9Understanding the Elements of

Design

Design is the process of describing, organizing, and structuring the components of a system at both the architectural level and at a detailed level Focused on construction Like developing blueprints

Three questions What components require systems design? What are the inputs to and outputs of the

design process? How is systems design done?

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9Inputs and Outputs: Moving from

Analysis to Design

Design: Converts functional models from

analysis into models that represent the solution

Focused on technical issues Requires less user involvement than

analysis

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9SDLC Phases with Design Phase ActivitiesFigure 9-4

Design and Integrate NetworkDesign the Application ArchitectureDesign the User InterfacesDesign the System InterfacesDesign and Integrate the DatabasePrototype for Design DetailsDesign and Integrate System Controls

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9Structured Approach to Designing

the Application Architecture

Application software programs Designed in conjunction with database and user

interfaces Hierarchy of modules

Documented with system flowcharts

Design internal program logic

Top-down approach DFDs with automation boundaries Structure charts

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9Structured Design Models

Figure 9-7

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Automation System Boundary

Partitions data flow processes into manual and automated systems

Processes can be inside or outside boundary

Data flows can be inside and outside of boundary

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9DFD with Automation System BoundaryFigure 9-8

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System Flowchart

Representation of various computer programs, files, databases, and associated manual processes

Graphically describes organization of subsystems

Can show type of system Batch Real time

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9Common System Flow Chart SymbolsFigure 9-9

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9System Flow Chart for RMO

Figure 9-11

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9

Structure Chart

Describes functions and subfunctions of each part of system

Shows relationships between modules of a computer program

Simple and direct method Each module performs a specific function Each layer in a program performs specific

activities

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9Structure Chart for Entire Payroll Program

Figure 9-14

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9The Create New Order DFD FragmentFigure 9-17

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9Exploded View of Create New Order DFDFigure 9-18

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9Rearranged Create New Order DFDFigure 9-19

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9First Draft of the Structure Chart

Figure 9-20