← VCE Software Development U3O2

Data flow diagram (Level 1): data stores and entities

On a Level 1 DFD, a data store is where data is held (e.g. a file or database). Entities sit outside the system and send or receive data. Both must match the context diagram.

Part of: VCE Software Development - U3O2 - Analysis and Design — Module 44, QCE Digital Solutions Unit 2 — Data-Driven Problems and Solution Requirements — Module 88, QCE Digital Solutions Unit 3 — Interactions Between Users, Data and Digital Systems — Module 26, QCE Digital Solutions Unit 4 — Digital Methods for Exchanging Data — Module 129, QCE Digital Solutions Unit 4 — Complex Digital Data Exchange Problems and Solution Requirements — Module 91

Understanding Data flow diagram (Level 1): data stores and entities in VCE Software Development U3O2

What it does: Consistency means no entities are added, removed or renamed between the context diagram and the Level 1 DFD. Flows connect stores to processes. A store should not connect directly to an entity or to another store, so a process sits in between. A data store holds data within the system. People or organisations outside the system are external entities. A data store is named with a noun describing the data held. An action such as Update is a process name.

Common mistakes: The Level 1 DFD must match the context diagram. Teacher is not an entity on the context diagram, so it cannot appear here. It should be Student. Every data flow between an entity and a process must be labelled with the data it carries. It should be Teacher -> 1.0: marks entered.

Class: _____________________  ·  Name: _____________________  ·  Date: _________

Free printable worksheet with full answer key — or add this module to a class and your students practise it interactively.

🖨 Print worksheet + answer key Add Data flow diagram (Level 1): data stores and entities to a class →

This module's key terms are also in a printable crossword (Modules 42–51) and word search (Modules 26–51).

Take this worksheet further — free with Cloodit

Each concept is reinforced from every angle — learned, then applied, then tested.

Learning
Duo
Which best describes a data store on a Level 1 DFD?
A person or organisation outside the system that sends data inA place inside the system where data is held, such as a file or database
Matches
Customer -> D1 Orders file
↓
An external entity is connected directly to a data store. Data must pass through a process first, such as 1.0 Record order.
Applying
Meanings
Term
Data store
Meaning
On a Level 1 DFD, a data store is where data is held (e.g. a file or database). Entities sit outside the system and send or receive data. Both must match the context diagram.
Practice
External entity: Student
Testing
Gaps
: D1 Orders
Check Answer
Spots
1Context entity: Student
2L1 entity: Teacher

Cloodit turns curriculum-aligned coding content into journeys students work through one biome at a time.

The 'Fox' badge — Cunning Debugger, one of Cloodit's 106 collectible badges
Students earn collectable badges

Over 100 of them, across seven natural biomes.

Study Buddy
Students build a real study resource

Turns their work into revision material ready for Flash Cards and Exam study.

Diamond Dash — one of Cloodit's live, competitive Sprint games
Students lock in with Sprints

Live, competitive practice for the start of the lesson or a teacher-led lesson finisher.

A Cloodit certificate of achievement, ready to personalise and print
Custom printable certificates

Honour your top performers, or encourage a student who's trying hard — ready to print in seconds.

Add to class →

Quick Questions

1. Which best describes a data store on a Level 1 DFD?
A. A place inside the system where data is held, such as a file or database ✓
B. A person or organisation outside the system that sends data in
A data store holds data within the system. People or organisations outside the system are external entities.
2. Which of these is an external entity on a Level 1 DFD?
A. Customer who submits an order ✓
B. Orders database
A customer sits outside the system and sends or receives data. The Orders database is a data store inside the system.
3. Which data flow is NOT allowed on a Level 1 DFD?
A. Customer (entity) straight to Orders (data store) ✓
B. Customer (entity) to Process Order (process)
Entities cannot send data directly to a data store. The data must pass through a process, such as Process Order.
4. Do data stores appear on the Level 0 context diagram?
A. Yes, every data store must be drawn around the system
B. No, the context diagram shows the system as one process with its entities only ✓
Level 0 shows the system as a single process with its entities and data flows. Data stores are revealed in Level 1.
5. The context diagram shows entities Student and Teacher. Which Level 1 DFD is consistent with it?
A. Level 1 adds a new entity, Principal, that was not in the context diagram
B. Level 1 shows Student and Teacher as the external entities ✓
External entities and their data flows must match the context diagram. Adding a new entity makes the diagrams inconsistent.

Match the Pairs

D1 | Student records → A data store on a Level 1 DFD, drawn as an open-ended rectangle with an ID and a name, showing where data is held
Parent (external entity) → An external entity that sits outside the system and sends data to it or receives data from it
A Level 1 DFD must keep the same external entities as the context diagram → Context diagram entities: Customer, Bank | Level 1 entities: Customer, Bank
Data in a store can only move to or from a process, never directly to an entity → Process 2.0 Check stock -> D2 Product file
Customer -> D1 Orders file → An external entity is connected directly to a data store. Data must pass through a process first, such as 1.0 Record order.
Context diagram: Customer only | Level 1: Customer, Supplier → The Level 1 DFD adds a Supplier entity that is not on the context diagram, so the two diagrams are inconsistent.

Key Term

Data store
On a Level 1 DFD, a data store is where data is held (e.g. a file or database). Entities sit outside the system and send or receive data. Both must match the context diagram.

Fill in the Blanks

1. Data store: D1 Orders
Hint: Type the two-word term for where a Level 1 DFD shows data being held, such as a file or database.
2. Entity: Customer
Hint: Type the term for a person, group or system outside the system that sends or receives data.
3. Context entity: Customer Level 1 entity: Customer
Hint: Type the entity name that must stay consistent with the context diagram.
4. Entities sit outside the system boundary
Hint: Type the word that describes where external entities sit relative to the system.
5. Store: D1 Orders Flow: 1.0 Process Order -> D1 Orders
Hint: Type the data store that the process sends data to, as named in the line above.

Spot the Error

Question 1
A Context entity: Student
B L1 entity: Teacher
C L1 store: D1 Student file
D Student -> 1.0 Enrol: form
Line B — The Level 1 DFD must match the context diagram. Teacher is not an entity on the context diagram, so it cannot appear here. It should be Student.
Question 2
A Entity: Teacher
B Teacher -> 1.0
C 1.0 -> D1: mark record
D D1 -> 2.0: mark record
Line B — Every data flow between an entity and a process must be labelled with the data it carries. It should be Teacher -> 1.0: marks entered.
Question 3
A Entity: Parent
B Store D1: Payment file
C Parent -> D1: payment
D 1.0 -> D1: payment record
Line C — An external entity cannot send data straight to a data store. The data must go through a process first, so it should be Parent -> 1.0: payment.
Question 4
A Process D1: Book catalogue
B Entity: Member
C Member -> 1.0: loan request
D 1.0 -> D1: loan record
Line A — D1 is a data store because it holds data (the book catalogue). It is not a process. It should be Store D1: Book catalogue.
Question 5
A Entity: Customer
B Store D1: Order file
C D1 -> Customer: order details
D 2.0 -> Customer: receipt
Line C — A data store cannot send data directly to an external entity. A process must read the data from the store and send it on, so it should be D1 -> 2.0: order details.

Student with a class code? Join your class →