Data Flow Diagrams Examples An Example Draw the

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Data Flow Diagrams Examples

Data Flow Diagrams Examples

An Example Draw the DFD for a distance education university.

An Example Draw the DFD for a distance education university.

The enrolment process works as follows: 1. Students send in an application form containing

The enrolment process works as follows: 1. Students send in an application form containing their personal details, and their desired course. 2. The university checks that the course is available and that the student has necessary academic qualifications. 3. If the course is available the student is enrolled in the course, and the university confirms the enrolment by sending a confirmation letter to the student. OR 4. If the course is unavailable the student is sent a rejection letter.

Steps for DFD 1. people/organisations/things that supply information to or use information from the

Steps for DFD 1. people/organisations/things that supply information to or use information from the system external entities (EE) 2. Actions/doing words/verbs => Processes (P) 3. Movement/exchange of information/data between external entities to processes, and processes to processes => data flows (DF) 4. store/record information/data => data stores(DS)

In Example 1. A student (EE) sends in an application form (DF) containing their

In Example 1. A student (EE) sends in an application form (DF) containing their personal details, and their desired course. 2. The university checks (P) that the course is available. 3. If the course is available the student is enrolled (P) in the course, and the university confirms (P) the enrolment by sending a confirmation letter (DF) that they are registered for the course to the student. OR 4. If the course is unavailable the student is sent a rejection letter (DF).

Context Diagram or 0 Level DFD

Context Diagram or 0 Level DFD

1 Level DFD External entity – Student Processes - Check available, Enrol student, Confirm

1 Level DFD External entity – Student Processes - Check available, Enrol student, Confirm Registration Data Flows - Application Form, Course Details, Course Enrolment Details, Student Details, Confirmation/Rejection Letter Data Stores - Courses, Students.

Creating Data Flow Diagrams Lemonade Stand Example

Creating Data Flow Diagrams Lemonade Stand Example

Creating Data Flow Diagrams Example The operations of a simple lemonade stand will be

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 • Old way: no Use-Case Diagram • 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

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

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 Labor

Creating Data Flow Diagrams Example 1. Create a list of activities Group these activities

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 Labor

Creating Data Flow Diagrams Example Create a context level diagram identifying the sources and

Creating Data Flow Diagrams Example Create a context level diagram identifying the sources and sinks (users). 2. Construct Context Level DFD (identifies sources and sink) Context Level DFD Order Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Labor CUSTOME R Product Served 0. 0 Lemona de System Payment Received Goods Payment Sales Forecast Production EMPLOYE Schedule E Pay Time Worked Purchase Order VENDOR

Creating Data Flow Diagrams Example Create a level 0 diagram identifying the logical subsystems

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 CUSTOME R Produce Product Store Product Order Raw Materials Pay for Labor Sales Forecast Customer Order Product Ordered Payment 2. 0 Production Producti Schedule Product Served on Received Goods VENDOR Purchase Order EMPLOYE E 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

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 CUSTOME R Customer Order Serve Product Collect Payment Produce Product Store Product Order Raw Materials Pay for Labor ORDER 1. 1 Record Order Severed Order Payment 1. 2 Receive Paymen t PAYMENT Request for Forecast 1. 3 Produce Sales Forecast

Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level

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 Labor 2. 1 Serve Product Quantity Severed RAW MATERIALS Production Schedule 2. 2 Produce Production Data 2. 3 Store Product Quantity Used INVENTOR TY Quantity Produced & Location Stored

Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level

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 Received Goods 3. 2 Receive Items Produce Product Store Product Order Raw Materials Pay for Raw Materials PURCHASE 3. 1 ORDER Produce Purchas e Order Quantity On-Hand RAW Quantity MATERIALS Payment Approval 3. 3 Pay Vendor Pay for Labor Payment RECEIVED ITEMS VENDOR

Creating Data Flow Diagrams Example Create a level 1 decomposing the processes in level

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 Calculat e Payroll Produce Product Store Product Unpaid time cards PAYROLL Payment Approval Order Raw Materials Pay for Raw Materials 4. 3 Pay Employ ee Pay for Labor Payment PAYMENT S

Process Decomposition 0. 0 Lemona de System Context Level 1. 0 Sale 1. 1

Process Decomposition 0. 0 Lemona de System Context Level 1. 0 Sale 1. 1 Record Order 1. 2 Receive Paymen t 2. 0 Producti on 2. 1 Serve Product 2. 2 Produce Product 2. 3 Store Product 3. 0 Procurement 3. 1 Produce Purchas e Order 3. 2 Receive Items 3. 3 Pay Vendor 4. 0 Payroll 4. 1 Record Time Worked 4. 2 Calculat e Payroll 4. 3 Pay Employ ee Level 0 Level 1