1. DATA FLOW DIAGRAMS
Budi Arifitama

2. Key Definitions Process model Data flow diagramming
A formal way of representing how a business operates
Illustrates the activities that are performed and how data moves among them
Data flow diagramming
A popular technique for creating process models

3. Key Definitions
Logical process models describe processes without suggesting how they are conducted
Physical process models include process implementation information

4. DFD Elements Process Data flow
An activity or function performed for a specific business reason
Manual or computerized
Data flow
A single piece of data or a logical collection of data
Always starts or ends at a process

5. DFD Elements Data Store External entity
A collection of data that is stored in some way
Data flowing out is retrieved from the data store
Data flowing in updates or is added to the data store
External entity
A person, organization, or system that is external to the system but interacts with it.

6. Naming and Drawing DFD Elements
Process
Data flow
Data store
External
entity

7. Key Definition
Balancing involves insuring that information presented at one level of a DFD is accurately represented in the next level DFD.

8. Context Diagram First DFD in every business process
Shows the context into which the business process fits
Shows the overall business process as just one process (process 0)
Shows all the external entities that receive information from or contribute information to the system

9. Context Diagram Lemonade System
0.0
Lemonade System
EMPLOYEE
CUSTOMER
Pay
Payment
Order
Context Level DFD
VENDOR
Purchase Order
Production Schedule
Received Goods
Time Worked
Sales Forecast
Product Served

10. Level 0 Diagram
Shows all the major processes that comprise the overall system – the internal components of process 0
Shows how the major processes are interrelated by data flows
Shows external entities and the major processes with which they interact
Adds data stores

11. DFD Level 0 Level 0 DFD Sales Forecast Customer Order Product Ordered
2.0
Production
EMPLOYEE
Production Schedule
1.0
Sale
3.0
Procure-ment
Sales Forecast
Product Ordered
CUSTOMER
Pay
Payment
Customer Order
VENDOR
Purchase Order
Order Decisions
Received Goods
Time Worked
Inventory
Product Served
4.0
Payroll

12. Level 1 Diagrams
Generally, one level 1 diagram is created for every major process on the level 0 diagram
Shows all the internal processes that comprise a single process on the level 0 diagram
Shows how information moves from and to each of these processes
If a parent process is decomposed into, for example, three child processes, these three child processes wholly and completely make up the parent process

13. Produce Purchase Order
DFD Level 1
3.1
Produce Purchase Order
Order Decision
PURCHASE ORDER
3.2
Receive Items
Received Goods
RAW MATERIALS
3.3
Pay Vendor
Quantity Received
Quantity On-Hand
RECEIVED ITEMS
VENDOR
Payment Approval
Payment

14. Basic Symbols Four basic symbols are:
A double square for an external entity--a source or destination of data.
An arrow for movement of data from one point to another.
A rectangle with rounded corners for the occurrence of transforming process.
An open-ended rectangle for a data store.

15. Basic Symbols

16. DFD Examples

17. Creating Data Flow Diagrams
Steps:
Create a list of activities
Construct Context Level DFD (identifies external entities and processes)
Construct Level 0 DFD (identifies manageable sub process )
Construct Level 1- n DFD (identifies actual data flows and data stores )
Check against rules of DFD

18. DFD Naming Guidelines External Entity  Noun Data Flow  Names of data
Process  verb phrase
a system name
a subsystem name
Data Store  Noun

19. Creating Data Flow Diagrams Lemonade Stand Example

20. Creating Data Flow Diagrams
Example
Steps:
The operations of a simple lemonade stand will be used to demonstrate the creation of dataflow diagrams.
Create a list of activities
Old way: no Use-Case Diagram
New way: use Use-Case Diagram
Construct Context Level DFD (identifies sources and sink)
Construct Level 0 DFD (identifies manageable sub processes )
Construct Level 1- n DFD (identifies actual data flows and data stores )

21. Creating Data Flow Diagrams
Example
Create a list of activities
Think through the activities that take place at a lemonade stand.
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product

22. Creating Data Flow Diagrams
Example
Create a list of activities
Also think of the additional activities needed to support the basic activities.
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor

23. Creating Data Flow Diagrams
Example
Create a list of activities
Group these activities in some logical fashion, possibly functional areas.
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor

24. Creating Data Flow Diagrams
Example
Construct Context Level DFD (identifies sources and sink)
Create a context level diagram identifying the sources and sinks (users).
0.0
Lemonade System
EMPLOYEE
CUSTOMER
Pay
Payment
Order
Context Level DFD
VENDOR
Purchase Order
Production Schedule
Received Goods
Time Worked
Sales Forecast
Product Served
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor

25. Creating Data Flow Diagrams
Example
Construct Level 0 DFD (identifies manageable sub processes )
Create a level 0 diagram identifying the logical subsystems that may exist.
Level 0 DFD
2.0
Production
EMPLOYEE
Production Schedule
1.0
Sale
3.0
Procure-ment
Sales Forecast
Product Ordered
CUSTOMER
Pay
Payment
Customer Order
VENDOR
Purchase Order
Order Decisions
Received Goods
Time Worked
Inventory
Product Served
4.0
Payroll
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor

26. Creating Data Flow Diagrams
Example
Construct Level 1- n DFD (identifies actual data flows and data stores )
Create a level 1 decomposing the processes in level 0 and identifying data stores.
Level 1 DFD
CUSTOMER
Customer Order
Request for Forecast
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor
ORDER
1.1
Record Order
1.3
Produce Sales Forecast
Severed Order
Payment
Sales Forecast
1.2
Receive Payment
PAYMENT

27. Creating Data Flow Diagrams
Example
Construct Level 1 (continued)
Create a level 1 decomposing the processes in level 0 and identifying data stores.
Level 1 DFD
Product Order
ORDER
2.1
Serve Product
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor
Quantity Severed
RAW MATERIALS
Production Schedule
2.2
Produce Product
Quantity Used
INVENTORTY
Production Data
2.3
Store
Product
Quantity Produced & Location Stored

28. Creating Data Flow Diagrams
Example
Construct Level 1 (continued)
Create a level 1 decomposing the processes in level 0 and identifying data stores.
Level 1 DFD
3.1
Produce Purchase Order
Order Decision
PURCHASE ORDER
3.2
Receive Items
Received Goods
RAW MATERIALS
3.3
Pay Vendor
Quantity Received
Quantity On-Hand
RECEIVED ITEMS
VENDOR
Payment Approval
Payment
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor

29. Creating Data Flow Diagrams
Example
Construct Level 1 (continued)
Create a level 1 decomposing the processes in level 0 and identifying data stores.
Level 1 DFD
Time Worked
TIME CARDS
4.1
Record Time Worked
Customer Order
Serve Product
Collect Payment
Produce Product
Store Product
Order Raw Materials
Pay for Raw Materials
Pay for Labor
Employee ID
EMPLOYEE
Payroll Request
4.2
Calculate Payroll
Unpaid time cards
PAYROLL
Payment Approval
4.3
Pay Employee
PAYMENTS
Payment

30. Process Decomposition
1.0
Sale
1.1
Record Order
1.2
Receive Payment
2.0
Production
2.1
Serve Product
2.2
Produce Product
2.3
Store
Product
0.0
Lemonade System
3.0
Procure-ment
3.1
Produce Purchase Order
3.2
Receive Items
3.3
Pay Vendor
4.0
Payroll
4.1
Record Time Worked
4.2
Calculate Payroll
4.3
Pay Employee
Context Level
Level 0
Level 1

31. Latihan Bagi Menjadi 10 kelompok
Buatlah sebuah Data Flow Diagram lengkap dengan DFD context diagram, Level0, dan level 1 dari sebuah sistem informasi akademik di trilogi.

32. DFD Example: Bus Garage Repairs
Buses come to a garage for repairs.
A mechanic and helper perform the repair, record the reason for the repair and record the total cost of all parts used on a Shop Repair Order.
Information on labor, parts and repair outcome is used for billing by the Accounting Department, parts monitoring by the inventory management computer system and a performance review by the supervisor.