Drawing a context diagram from a scenario
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. A scenario says: 'Students use a library app to borrow books, and the app sends overdue notices to students.' How should you draw the system on a context diagram?
2. When reading a scenario to find external entities, what should you look for?
3. A scenario says: 'A customer enters their order details into the website.' Which data flow label is best for the arrow from Customer to the system?
4. You have finished drawing your context diagram. Which check should you do?
5. Which is a common mistake when drawing a context diagram from a scenario?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1Library System (one central process box) | AA labelled data flow arrow from an external entity into the system, showing what data enters | |
| 2Member --> [ book request ] --> Library System | BThe whole system is drawn as ONE process in the centre, named after the system, with no internal detail | |
| 3Reading a scenario: each person, organisation or other system that sends data to or receives data from the system is an external entity | CThe data flow arrow is missing a label, so we cannot tell what data is moving between the entity and the system | |
| 4Checking every flow has a label: each arrow shows the data it carries and the direction of travel | DA data store is drawn in a context diagram and the flow bypasses the system, but context diagrams show only the system process and external entities | |
| 5Member --> Library System (no label on the arrow) | EEntities: Member, Librarian, Publisher | |
| 6Member --> [ book request ] --> Catalogue Database | FLibrary System --> [ overdue notice ] --> Member |
C
Definitions
context diagram
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
Context diagram processes: _
2.
Scenario: Parent sends payment details.
Parent --> School System : _______________
3.
Scenario: A coach views the team roster.
External entity: _____
4.
Scenario: System sends report to teacher.
Marks System ___ Teacher : Report
5.
Context diagram: data stores = _
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
System: Canteen Order App
B
Entity: Canteen Order App
C
Student -> System: order
D
System -> Student: receipt
Question 2
A
System: Gym Booking App
B
Entity: Booking database
C
Entity: Trainer
D
Member -> System: booking
E
System -> Trainer: roster
Question 3
A
System: Library Loan App
B
Entity: Member
C
Member -> System: book request
D
System -> Member:
Question 4
A
Entity: Parent
B
System: Validate and Store
C
Parent -> System: fee payment
D
System -> Parent: receipt
Question 5
A
System: Clinic Booking App
B
Entity: Patient
C
System -> Patient: booking
D
System -> Patient: reminder
Answer Key
Drawing a context diagram from a scenario
Section A: Quick Questions
Q1
B — One central process named 'Library app' with Student as an external entity
Q2
B — People, organisations or other systems outside the software that send data in or receive data out
Q3
A — Order details
Q4
A — Every arrow has a label naming the data and a direction showing where it goes
Q5
A — Drawing a data flow directly between two external entities
Section B: Match the Pairs
Q1
Library System (one central process box) → The whole system is drawn as ONE process in the centre, named after the system, with no internal detail
Q2
Member --> [ book request ] --> Library System → A labelled data flow arrow from an external entity into the system, showing what data enters
Q3
Reading a scenario: each person, organisation or other system that sends data to or receives data from the system is an external entity → Entities: Member, Librarian, Publisher
Q4
Checking every flow has a label: each arrow shows the data it carries and the direction of travel → Library System --> [ overdue notice ] --> Member
Q5
Member --> Library System (no label on the arrow) → The data flow arrow is missing a label, so we cannot tell what data is moving between the entity and the system
Q6
Member --> [ book request ] --> Catalogue Database → A data store is drawn in a context diagram and the flow bypasses the system, but context diagrams show only the system process and external entities
Section C: Definitions
Q1
context diagram — Shows the whole system as one process, with the external entities around it and a labelled data flow arrow for each piece of data going in or out. Built by reading a scenario.Section D: Fill in the Blanks
Q1
Context diagram processes: 1Q2
Scenario: Parent sends payment details.
Parent --> School System : Payment detailsQ3
Scenario: A coach views the team roster.
External entity: CoachQ4
Scenario: System sends report to teacher.
Marks System --> Teacher : ReportQ5
Context diagram: data stores = 0Section E: Spot the Error
Q1
B — The app is the system, not an external entity. The entity is the person or group outside it, so line 2 should be 'Entity: Student'.
Q2
B — A database is stored inside the system, so it is not an external entity. Line 2 should name an outside entity such as 'Entity: Member'.
Q3
D — Every data flow must have a label naming the data that moves. Line 4 should be 'System -> Member: loan receipt'.
Q4
B — A context diagram shows the whole system as one process with one name. Splitting it into steps belongs in a Level 1 DFD. It should be 'System: School Payment App'.
Q5
C — The patient supplies the booking details, so the arrow must point from the patient into the system: 'Patient -> System: booking'.