DFD Examples
DFD Notation
• Data Flow : labeled arrow
• Sources and sinks of information/data
(also called external entity)
• Process
or
or
• Available data (data store)
or
Example: Air line reservation
DFD Example 1: Payroll
DFD Example 2: Old Car Mart
• Buys and sells old cars; has large number in
stock: different models, make, year,colors,…
• Does some repairs for adding value; records
kept; has own garage
• Advertise in news papers
• Salesmen hired on commission basis to handle
customers, negotiate, etc.
• Needs to take stocks; prepare summary of
sales, profits, etc; pay salesmen
Prepare DFD
Example 3: Book Supplier
• Supplies books to customers; no stocks
maintained; books sourced directly from
publishers
• Prepare context diagrams
Book Supplier: Exploding Process
2