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 вЂў External Entity пѓ Noun вЂў Data Flow пѓ Names of data вЂў Process пѓ verb phrase вЂ“ a system name вЂ“ a subsystem name вЂў Data Store пѓ Noun Creating Data Flow Diagrams Lemonade Stand Example Creating Data Flow Diagrams Example The operations of a simple lemonade stand will be used to demonstrate the creation of dataflow diagrams. Steps: 1. Create a list of activities вЂў Old way: no Use-Case Diagram вЂў 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 sources and sinks (users). Context Level DFD Order Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor CUSTOMER Sales Forecast 0.0 Lemonade Production Schedule EMPLOYEE Pay System Product Served Payment Received Goods Payment VENDOR Time Worked Purchase Order Creating Data Flow Diagrams Example Create a level 0 diagram identifying the logical subsystems that may exist. 3. Construct Level 0 DFD (identifies manageable sub processes ) Level 0 DFD 1.0 Sale Customer Order Serve Product Collect Payment Product Ordered Payment CUSTOMER Produce Product Store Product Pay for Labor Product Served Received Goods VENDOR Order Raw Materials Pay for Raw Materials Sales Forecast Customer Order Purchase Order Production Schedule 2.0 Production EMPLOYEE Inventory 3.0 Procurement Payment Order Decisions Pay 4.0 Payroll Time Worked Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level 0 and identifying data stores. 4. Construct Level 1- n DFD (identifies actual data flows and data stores ) Level 1 DFD CUSTOMER Customer Order ORDER Customer Order Serve Product Collect Payment 1.1 Record Order Severed Order Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor Payment 1.2 Receive Payment PAYMENT Request for Forecast 1.3 Produce Sales Forecast Sales Forecast Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level 0 and identifying data stores. 4. Construct Level 1 (continued) Level 1 DFD Product Order ORDER Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Raw Materials Pay for Labor 2.1 Serve Product Quantity Severed RAW MATERIALS Production Schedule 2.2 Produce Product Production Data 2.3 Store Product Quantity Used INVENTORTY Quantity Produced & Location Stored Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level 0 and identifying data stores. Customer Order Serve Product Collect Payment 4. Construct Level 1 (continued) Level 1 DFD Order Decision 3.1 Produce Purchase Order PURCHASE ORDER Quantity On-Hand Quantity Received Received Goods 3.2 Receive Items Produce Product Store Product Payment Approval Order Raw Materials Pay for Raw Materials 3.3 Pay Vendor Pay for Labor Payment RAW MATERIALS RECEIVED ITEMS VENDOR Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level 0 and identifying data stores. Customer Order Serve Product Collect Payment 4. Construct Level 1 (continued) Level 1 DFD Time Worked 4.1 Record Time Worked TIME CARDS Employee ID EMPLOYEE Payroll Request 4.2 Calculate Payroll Produce Product Store Product Unpaid time cards PAYROLL Payment Approval Order Raw Materials Pay for Raw Materials 4.3 Pay Employe e Pay for Labor Payment PAYMENTS Process Decomposition 0.0 Lemonade System Context Level 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 3.0 Procurement 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 Employe e Level 0 Level 1 DFD Example: Bus Garage Repairs вЂў Buses come to a garage for repairs. вЂў 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. вЂў 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. DFD Example: Bus Garage Repairs (contвЂ™d) вЂў External Entities: Bus, Mechanic, Helper, Supervisor, Inventory Management System, Accounting Department, etc. вЂў Key process (вЂњthe systemвЂќ): performing repairs and storing information related to repairs вЂў Processes: вЂ“ вЂ“ вЂ“ вЂ“ вЂ“ Record Bus ID and reason for repair Determine parts needed Perform repair Calculate parts extended and total cost Record labor hours, cost DFD Example: Bus Garage Repairs (contвЂ™d) вЂў Data stores: вЂ“ вЂ“ вЂ“ вЂ“ Personnel file Repairs file Bus master list Parts list вЂў Data flows: вЂ“ вЂ“ вЂ“ вЂ“ вЂ“ Repair order Bus record Parts record Employee timecard Invoices Bus Garage Context Diagram Bus Fixed mechanical problems Mechanical problem to be repaired Helper Labor Bus Repair Process System Labor Mechanic Labor, parts cost details Repair summary List of parts used Supervisor Inventory Management System Accounting CSUB BurgerвЂ™s Order Processing System вЂў Draw the CSUB BurgerвЂ™s context diagram вЂ“ System вЂў Order processing system вЂ“ External entities вЂў Kitchen вЂў Restaurant вЂў Customer вЂ“ Processes вЂў вЂў вЂў вЂў Customer order Receipt Food order Management report