Architecture Diagrams

Data Flow Diagram

• Graphical representation of system’s flow of information
• How data is processed by a system in terms of inputs , outputs and where that information is stored.

Data Flow Diagram symbols are standardized notations

• External entity
  • Represented in rectangles with a short-text labels haveing the Domain o
  • Outside system that sends or receives data
  • Might be an outside organization or person, a computer system or a business system
• Process
  • Represented in circle with a short-text labels have Process action
  • Any process that changes the data, producing an output
• Data store
  • Represented in Data rectagles (with right border open) with a short-text labels having what Model is stored
  • Files or repositories that hold information for later use
• Data flow
  • Represented in Arrow with a short-text labels having what data is flowing
  • route that data takes between the external entities, processes and data stores

DFD rules and tips

• Each process should have at least one input and an output.
• Each data store should have at least one data flow in and one data flow out.
• Data stored in a system must go through a process.
• All processes in a DFD go to another process or a data store.

Levels

Level 0

• Shows Boundry of the System
• It’s called Context Diagram