Skip to main content

Short note: structured design

Short answer

Structured design uses top‑down decomposition to create a hierarchy of independent modules with high cohesion and low coupling. It converts data flow diagrams into structure charts showing module calls and data flow, making systems easier to understand, test, and maintain, though it separates data from processes.

Write a short note on Structured design.

Structured design is a design methodology that breaks a system into a hierarchy of small, independent modules, using top-down decomposition. It follows structured analysis (data flow diagrams) and converts it into a modular program structure.

Key ideas

  • Top-down decomposition: start with the whole system and refine it into sub-functions until each module does one task.
  • Modularity: each module has a single, well-defined function.
  • High cohesion: elements inside a module are closely related.
  • Low coupling: modules depend on each other as little as possible and communicate by simple parameters.
  • Hierarchical control: a boss module calls subordinate modules.

Tools

  • Data flow diagram (DFD): input to design.
  • Structure chart: shows modules, the calling hierarchy and data passed between them.
  • Data dictionary and pseudo-code/decision tables for module logic.
        [Main Program]
        /     |      \
  [Input] [Process] [Output]
            /   \
        [Calc] [Validate]

Advantages

Easy to understand, test and maintain; modules can be reused; work can be divided among team members; errors are easy to locate.

Limitation

Separates data from processes, so it is less suitable for very large or changing systems than object-oriented design.

✓ Answer checked by Claude Opus 5.5 (high effort)

Related questions

All Information System chapter 5 questions →