1. DFD Examples

2. DFD Notation Data Flow : labeled arrow
Sources and sinks of information/data (also called external entity) or
Process or
Available data (data store) or

3. Example: Air line reservation

4. DFD Example 1: Payroll

5. 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

7. Example 3: Book Supplier
Supplies books to customers; no stocks maintained; books sourced directly from publishers
Prepare context diagrams

10. Book Supplier: Exploding Process 2