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Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
Dfd examples
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Dfd examples

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  • 1. • A data flow diagram (DFD) is a graphical representation of the "flow" of data through an information system.• DFDs can also be used for the visualization of data processing (structured design).• It views a system as a function that transform the input into desired output .
  • 2. • Flow chart shows “ flow of Control “ .• DFD shows “ flow of Data• The flowchart describes boxes that describe computations, decisions, interactions & loops.• It is important to keep in mind that data flow diagrams are not flowcharts and should not include control elements .
  • 3. • Processes on DFDs can operate in parallel (at-the- same-time)o Processes on flowcharts execute one at a time• DFDs show the flow of data through a systemo Flowcharts show the flow of control (sequence and transfer of control)• Processes on a DFD can have dramatically different timing (daily, weekly, on demand)o Processes on flowcharts are part of a single program with consistent timing
  • 4. Creating Data Flow Diagrams Steps:1. Create a list of activities2. 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
  • 5. Creating Data Flow Diagrams Lemonade Stand Example
  • 6. Creating Data Flow Diagrams Example Steps:The operations of a simple 1. Create a list of activitieslemonade stand will be used 2. Construct Context Level DFDto demonstrate the creation (identifies sources and sink)of dataflow diagrams. 3. Construct Level 0 DFD (identifies manageable sub processes ) 4. Construct Level 1- n DFD (identifies actual data flows and data stores )
  • 7. Creating Data Flow Diagrams Example 1. Create a list of activitiesThink through the activitiesthat take place at a lemonadestand. Customer Order Serve Product Collect Payment Produce Product Store Product
  • 8. Creating Data Flow Diagrams Example 1. Create a list of activitiesAlso think of the additionalactivities needed to supportthe basic activities. Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor
  • 9. Creating Data Flow Diagrams Example 1. Create a list of activitiesGroup these activities insome 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
  • 10. Creating Data Flow Diagrams Example 2. Construct Context Level DFD (identifies sources and sink)Create a context leveldiagram identifying the Context Level DFDsources and sinks (users). Sales Forecast Order 0.0 CUSTOMER Lemonade Production Schedule EMPLOYEECustomer Order Product Served System PayServe Product Payment Time WorkedCollect Payment Received Goods Payment Purchase OrderProduce ProductStore Product VENDOROrder Raw MaterialsPay for Raw MaterialsPay for Labor
  • 11. Creating Data Flow Diagrams Example 3. Construct Level 0 DFDCreate a level 0 diagram (identifies manageable sub processes )identifying the logical Level 0 DFDsubsystems that may exist. 1.0 Sale Customer Order Sales ForecastCustomer Order Product OrderedServe Product PaymentCollect Payment 2.0 Production CUSTOMER EMPLOYEE Production Schedule Product ServedProduce Product Received Goods InventoryStore Product 3.0 VENDOR Procure- Order Purchase OrderOrder Raw Materials ment DecisionsPay for Raw Materials Payment Pay Time WorkedPay for Labor 4.0 Payroll
  • 12. Creating Data Flow Diagrams Example 4. Construct Level 1- n DFDCreate a level 1 (identifies actual data flows and data stores )decomposing the processes Level 1 DFDin level 0 and identifying CUSTOMERdata stores. Customer Order ORDER Request for ForecastCustomer Order 1.1Serve Product RecordCollect Payment Order 1.3 Produce Severed Order SalesProduce Product Payment Forecast Sales ForecastStore Product 1.2 Receive PAYMENT PaymentOrder Raw MaterialsPay for Raw MaterialsPay for Labor
  • 13. Creating Data Flow Diagrams Example 4. Construct Level 1 (continued)Create a level 1decomposing the processes Level 1 DFDin level 0 and identifying Product Orderdata stores. ORDERCustomer Order 2.1 Serve Quantity SeveredServe Product ProductCollect Payment RAW Production MATERIALS ScheduleProduce Product 2.2Store Product Produce Quantity Used Product INVENTORTYOrder Raw Materials Production DataPay for Raw Materials 2.3 Quantity Produced & Store Location StoredPay for Labor Product
  • 14. Creating Data Flow Diagrams Example 4. Construct Level 1 (continued)Create a level 1decomposing the processes Level 1 DFDin level 0 and identifying Order Decision PURCHASEdata stores. 3.1 ORDER Produce PurchaseCustomer Order Order Quantity On-HandServe Product RAW Quantity MATERIALSCollect Payment Received Received Goods 3.2Produce Product Receive ItemsStore Product RECEIVED ITEMS Payment ApprovalOrder Raw Materials VENDORPay for Raw Materials 3.3 Pay VendorPay for Labor Payment
  • 15. Creating Data Flow Diagrams Example 4. Construct Level 1 (continued)Create a level 1decomposing the processes Level 1 DFDin level 0 and identifying Time Workeddata stores. 4.1 TIME CARDS Record TimeCustomer Order Worked Employee IDServe Product EMPLOYEECollect Payment Payroll Request 4.2 Unpaid time cardsProduce Product Calculate PayrollStore Product PAYROLL Payment ApprovalOrder Raw Materials 4.3Pay for Raw Materials Pay Employe e PAYMENTSPay for Labor Payment
  • 16. 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 eContext Level Level 0 Level 1

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