Systems Design Techniques

Systems Design Techniques

Logical and Physical Design

  • Logical design refers to the abstract representation of the data flow and inputs/outputs of the system, whereas physical design translates the logical design into a specific physical system.
  • An important outcome of the logical design phase is the Data Dictionary, a comprehensive description of every data element and their interrelationships.
  • During the physical design, Documents, Screens, and Reports Design (DSR) are specified to portray how the user performs their roles in the new system.
  • The Database Design involves defining the specific tables, fields, keys, and relationships in a database from the entity-relationship diagram (ERD) in logical design.

Design Methods

  • Top-down design (also known as stepwise design) decomposes a system into subsystems or components in a hierarchy.
  • Bottom-up design involves designing individual components first and then integrating to form a whole.
  • Object-oriented design (OOD) constructs a system as a collection of interacting objects, each representing an instance of a class.
  • Structured design is a design method where a system is subdivided into modules and then relationships between the modules are identified.

Design Processes

  • In the modularisation process, the system is broken down into subsystems or modules.
  • Design documentation provides a detailed description of how a system or subsystem performs its role or function, and is crucial for maintenance and troubleshooting.
  • The Prototyping Process involves developing an initial working model of the system, demonstrating its functionality to stakeholders for feedback.

Interface Design

  • User Interface Design aims to make user interaction as simple and efficient as possible.
  • The Graphical User Interface (GUI) allows the user to interact with electronic devices through graphical icons and visual indicators.

Algorithm Design

  • Algorithm design involves deciding on the most efficient method to execute each operation defined during functional decomposition.
  • Flowcharts and Pseudocode are methods used to represent algorithms for easier understanding and debugging.