DFD (DATA FLOW DIAGRAM)
• Graphically characterize data processes and flows in a business system
• System inputs
Atiya MasoodAtiya Page 1
Creating the Context Diagram
• The highest level in a data flow diagram
• Contains only one process, representing the entire system
• The process is given the number 0
• All external entities, as well as Major data flows are shown
• The diagram does not contain any data stores.
Draw the DFD for a distance education university. The enrolment process works as follows:
Students send in an application form containing their personal details, and their desired
The university checks that the course is available and that the student has necessary
If the course is available the student is enrolled in the course, and the university confirms the
enrolment by sending a confirmation letter to the student.
If the course is unavailable the student is sent a rejection letter.
Read the problem description carefully looking for:
people/organisations/things that supply information to or use information from the
system => external entities (EE)
actions/doing words/verbs => Processes (P)
movement/exchange of information/data between external entities to
processes, and processes to processes => data flows (DF)
store/record information/data => data stores(DS)
book lending library
Q2 The library receives details of books, and orders books from one or more book
Books may be reserved and borrowed by members of the public, who are
required to give a borrower number. The library will notify borrowers when a
Atiya MasoodAtiya Page 2
reserved book becomes available or when a borrowed book becomes overdue.
In addition to supplying books, a book supplier will furnish details of specific
books in response to library enquiries from brower.
Q3 Consider Hoosier Burger a functional restaurant in Bloomington, Indiana, owned
by Bob and Thelma. Many people , student and faculty, frequently eat at Hossier
Burger . The restaurant uses an information system that take customer orders send the
order to kitchen , Manager monitor goods sold and inventory and generate for
management report . Customer gets receipt after eating.
Precision Tools sells a line of high-quality woodworking tools. When customers place
orders on the company’s Web site, the system checks to see if the items are in stock,
issues a status message to the customer, and generates a shipping order to the
warehouse, which fills the order. When the order is shipped, the customer is billed.
The system also produces various inventory reports to accounting department.
Draw a context diagram for the order system
Q5 Perfect Pizza wants to install a system to record orders for pizza and chicken wings. When
regular customers call Perfect Pizza on the phone, they are asked their phone number. When
the number is typed into a computer, the name, address, and last order date is automatically
brought up on the screen. Once the order is taken, the total, including tax and delivery, is
calculated. Then the order is given to the cook. A receipt is printed. Occasionally, special
offers (coupons) are printed so the customer can get a discount. Drivers who make deliveries
give customers a copy of the receipt and a coupon (if any).Weekly totals are kept management
for comparison with last year’s performance. Write a summary of business activities for
taking an order at Perfect Pizza.
Atiya MasoodAtiya Page 3