Understanding Data Flow Diagrams (DFD) with an Airline Ticket Booking Example

Data Flow Diagram (DFD) is a graphical tool that helps users understand and analyze system data flows by describing functions, inputs, outputs, and data stores logically.

Components of DFD

Data Flow : a named flow of data between processes or stores.

Process : transformation of input data to output.

Data Store : temporary storage with a name.

External Entity : people or organizations outside the system.

Basic Symbols (Key)

Box: represents the source or destination of data.

Circle or ellipse: represents a process (加工).

Arrow: indicates the direction of data flow.

Double line: denotes a data store.

Practical Example – Airline Ticket Booking System

The case study walks through the DFD creation for a flight reservation system, identifying external entities (airline, passenger), data flows (flight information, booking requests), processes (arrange flight, store booking, print ticket), and data stores (booking information).

Subsequent diagrams illustrate storing flight information, passenger input, system queries, ticket printing, and final delivery to the passenger.

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