This document discusses program design, including moving from logical to physical data flow diagrams, using structure charts to illustrate program organization and interaction, guidelines for building structure charts, and creating program specifications. The key points are physical DFDs show implementation details; structure charts show program components at a high level; guidelines include high cohesion, loose coupling, and assessing fan-in and fan-out; and specifications provide instructions for programmers.

1. HI-600: Analysis and Design of Health Information Systems
Design: Part IV
Program Design

2. Logical to Physical Process Models - DFD

3. Physical Data Flow Diagrams (DFDs)

4. Physical Processes
Logical Process Sample Physical Process Implementations
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Quickbooks

5. Physical Data Flows

6. Physical Data Stores

7. DESIGNING PROGRAMS
• Designing modular, flexible and maintainable
system
• Program design: top-down modular approach:
• A high-level diagram, called structure chart, is created
to illustrate the organization and interaction of the
different pieces of code within the program.
• Program specifications are written to describe what
needs to be included in each program module.

8. Structure Chart Syntax

9. Building the Structure Chart

10. Steps in Building the Structure Chart
1. Identify modules and levels
2. Identify special connections
3. Add couples
4. Revise structure chart

11. Design Guidelines
• Build Modules with High Cohesion
• Build Loosely Coupled Modules
• Create High Fan-In
• Avoid High Fan-Out
• Assess the Chart for Quality

12. Loose Coupled Modules w/ High Cohesion

13. Create High Fan-In and Avoid High Fan-Out

14. Assess the Chart for Quality

15. PROGRAM SPECIFICATION

16. SUMMARY
• Moving from logical to physical process models
– Physical DFDs show implementation details
• Structure chart
– The structure chart shows all of the functional components needed in
the program at a high level
• Building structure chart
• Module, control connection, couples, review
• Structure chart design guidelines
• Cohesion, coupling, and fan-in/fan-out
• Program specifications
– Program specifications provide more detailed instructions to the
programmers.