DFD Examples by E55vHG

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									DFD Examples

  Yong Choi
    BPA
   CSUB
      Creating Data Flow Diagrams
 Steps:

1. Create a list of activities
2. Construct Context Level DFD
   (identifies external entities and processes)
3. Construct Level 0 DFD
   (identifies manageable sub process )
4. Construct Level 1- n DFD
   (identifies actual data flows and data stores )
5. Check against rules of DFD
    DFD Naming Guidelines

• External Entity  Noun
• Data Flow  Names of data
• Process  verb phrase
  – a system name
  – a subsystem name
• Data Store  Noun
Creating Data Flow Diagrams
 Lemonade Stand Example
           Creating Data Flow Diagrams
       Example                Steps:
The operations of a simple    1. Create a list of activities
lemonade stand will be used
                                  •    Old way: no Use-Case Diagram
to demonstrate the creation
of dataflow diagrams.             •    New way: use Use-Case Diagram
                              2. Construct Context Level DFD
                                 (identifies sources and sink)
                              3. Construct Level 0 DFD
                                 (identifies manageable sub processes )
                              4. Construct Level 1- n DFD
                                 (identifies actual data flows and data stores )
            Creating Data Flow Diagrams
       Example                  1. 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
            Creating Data Flow Diagrams
       Example                 1. 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
            Creating Data Flow Diagrams
       Example               1. 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
            Creating Data Flow Diagrams
       Example               2. Construct Context Level DFD
                                (identifies sources and sink)
Create a context level
diagram identifying the
                                            Context Level DFD
sources and sinks (users).
                                                                       Sales Forecast
                                             Order            0.0
                              CUSTOMER                     Lemonade Production Schedule EMPLOYEE
Customer Order                           Product Served     System        Pay
Serve Product                               Payment                      Time Worked
Collect Payment                                  Received Goods
                                                    Payment
                                                                    Purchase Order
Produce Product
Store Product                                              VENDOR


Order Raw Materials
Pay for Raw Materials

Pay for Labor
            Creating Data Flow Diagrams
       Example               3. Construct Level 0 DFD
Create a level 0 diagram        (identifies manageable sub processes )
identifying the logical                              Level 0 DFD
subsystems that may exist.
                                                              1.0
                                                              Sale
                                    Customer Order                                Sales Forecast
Customer Order
                                                        Product Ordered
Serve Product
                                                 Payment
Collect Payment                                                2.0             Production
                              CUSTOMER                                                        EMPLOYEE
                                                            Production          Schedule
                                           Product Served
Produce Product
                                         Received Goods           Inventory
Store Product
                                                              3.0
                               VENDOR                       Procure-        Order
                                           Purchase Order
Order Raw Materials                                          ment          Decisions
Pay for Raw Materials                      Payment
                                                                         Pay         Time Worked

Pay for Labor                                                 4.0
                                                             Payroll
           Creating Data Flow Diagrams
       Example                4. Construct Level 1- n DFD
Create a level 1                 (identifies actual data flows and data stores )
decomposing the processes                               Level 1 DFD
in level 0 and identifying
                                                           CUSTOMER
data stores.
                              Customer Order
                                                             ORDER
                                                                           Request for Forecast
Customer Order
                                                1.1
Serve Product                                  Record
Collect Payment                                Order                       1.3
                                                                         Produce
                                                         Severed Order    Sales
Produce Product              Payment                                     Forecast
                                                                                     Sales Forecast
Store Product
                                             1.2
                                           Receive          PAYMENT
                                           Payment
Order Raw Materials
Pay for Raw Materials

Pay for Labor
           Creating Data Flow Diagrams
       Example               4. Construct Level 1 (continued)
Create a level 1
decomposing the processes                              Level 1 DFD
in level 0 and identifying
                             Product Order
data stores.
                                                              ORDER
Customer Order                                 2.1
                                              Serve       Quantity Severed
Serve Product                                Product
Collect Payment                                                 RAW
                             Production
                                                              MATERIALS
                              Schedule
Produce Product                                2.2
Store Product                                Produce    Quantity Used
                                             Product

                                                            INVENTORTY
Order Raw Materials                Production Data
Pay for Raw Materials
                                               2.3       Quantity Produced &
                                              Store      Location Stored
Pay for Labor                                Product
           Creating Data Flow Diagrams
       Example               4. Construct Level 1 (continued)
Create a level 1
decomposing the processes                                 Level 1 DFD
in level 0 and identifying    Order Decision
                                                                         PURCHASE
data stores.                                      3.1                     ORDER
                                               Produce
                                               Purchase
Customer Order                                  Order         Quantity On-Hand
Serve Product                                                               RAW
                                                           Quantity       MATERIALS
Collect Payment                Received                   Received
                                Goods
                                                  3.2
Produce Product                                Receive
                                                Items
Store Product                                                               RECEIVED
                                                                             ITEMS
                                          Payment Approval
Order Raw Materials
                                                                             VENDOR
Pay for Raw Materials                           3.3
                                                Pay
                                               Vendor
Pay for Labor
                                 Payment
           Creating Data Flow Diagrams
       Example               4. Construct Level 1 (continued)
Create a level 1
decomposing the processes                                  Level 1 DFD
in level 0 and identifying   Time Worked

data stores.                                     4.1                 TIME CARDS
                                               Record
                                                Time
Customer Order                                 Worked         Employee ID
Serve Product                                                          EMPLOYEE
Collect Payment
                             Payroll Request
                                                  4.2
                                                                   Unpaid time cards
Produce Product                                Calculate
                                                Payroll
Store Product                                                               PAYROLL

                                          Payment Approval
Order Raw Materials
                                                 4.3
Pay for Raw Materials                            Pay
                                               Employe
                                                  e                  PAYMENTS
Pay for Labor
                                Payment
               Process Decomposition
                                   1.1        1.2
                      1.0
                                  Record    Receive
                      Sale
                                  Order     Payment




                                    2.1       2.2         2.3
                       2.0
                                   Serve    Produce      Store
                    Production
                                  Product   Product     Product


       0.0
    Lemonade
     System
                                    3.1
                       3.0                     3.2       3.3
                                 Produce
                     Procure-               Receive      Pay
                                 Purchase
                      ment                   Items      Vendor
                                  Order




                                    4.1                   4.3
                                               4.2
                      4.0         Record                  Pay
                                            Calculate
                     Payroll       Time                 Employe
                                             Payroll
                                  Worked                   e



Context Level      Level 0       Level 1

								
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