CFICSE

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CFICSE

• Structured Analysis and Design
• Methodology - SA01

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Presentation Outline

• 1. Introductions and Backgrounds
• 2. Course Layout and Approach
• 3. Definitions and Elements of Structured
  Analysis and Design
• 4. SADM and the Software Life Cycle
• 5. Strengths and Weaknesses of SADM
• 6. SADM versus OOAD

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2. Course Layout and Approach

• throw out the original notes
• Six periods covering
• Introduction (1 class)
• Requirements Analysis and Specification (1 class)
• Structured Analysis (3 classes)
• Structured Design (1 class)
• Healthy dose of lessons learned and examples

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3. Definitions

• Structured Analysis
• one of two analysis models which have prevailed
  over the past two decades
• an amalgam of methods applied by numerous
  authors
• iterative model building activity (data, process
  and event)
• includes a set of diagramatic tools and standard
  notation
• decomposition oriented

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• Structured Design
• the means by which the software model is
  transformed from the outputs of the structured
  analysis to program structures
• iteratively transform the SA models into logical
  and physical components
• again decomposition oriented
• and again employs a set of diagramatic tools
• relies heavily upon natural language to add
  meaning to earlier abstractions

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The Elements of Structured Analysis
Process Model
Data Model
Data Flow Diagram
Data Dictionary
Entity - Relationship Diagram
State Transition Diagram
Event Model
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The Elements of Structured Design

• Structure Charts
• Program Design Language or pseudo-code
• Design Data Dictionary

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4. SADM and The Software Life Cycle

• The Waterfall and the influence of MIL-STD-2167A
• and vice versa

Deployment
SOR ---- ----
SRS ---- ----
PDD ---- ----
DDD ---- ----
Maintenance
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5. Strengths of Structured Analysis and Design

• huge improvement over ad-hoc and flowcharting
  methods applied early in software development
• consistent with the nature of structured (3rd
  Gen) programming languages (Pascal, C, ADA)
• allowed for the development of larger, more
  complex systems (decomposition and I/F
  specifications)
• methods are easy to understand and use

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Weaknesses of Structured Analysis and Design

• non-trivial mapping from analysis to design
• structure and behaviour are separated in the
  model
• fundamentally unstable change is difficult
• limited chance for re-use
• lacks support for serious scalability
• difficult to achieve and maintain levels of
  reliability and safety
• difficult to apply to real-time

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Example - EST Electronic Support and Training
Systems Project
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6. Structured vs Object Oriented Analysis and
Design

• Requirement Specification
• Entities
• E-R Diagrams
• Data Flow Diagrams
• State Transition Diagrams
• Data Dictionaries
• Structure Charts
• Program Deign Language

• Use Case Diagrams
• Objects
• Collaboration Diagrams
• Sequence Diagrams
• State Transition Diagrams
• Class Diagrams Packages
• Component Diagram
• Unified Modelling Language
• Deployment Diagrams

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Why teach Structured Analysis and Design ?