1. www.company.com Lab 3 Data Flow Diagram CPIT 250 System Analysis and Design

2. www.company.com Outline: System Development Life Cycle Data Flow Diagram –What is Data Flow Diagram (DFD) ? –Diagram Notations –Developing data flow diagram Context diagram Level-0 diagram CPIT 250 System Analysis and Design

3. www.company.com System Analysis and Design Different phases of system development life cycle: CPIT 250 System Analysis and Design

4. www.company.com Data Flow Diagram What is Data Flow diagram ? –It is a graphical representation of the "flow" of data through system –It shows 1.What kind of information will be input to and output from the system, 2.Where the data will come from and go to, 3.How data can flow through system 4.Where the data will be stored. –It does not show 1.Information about the timing of processes, 2.Information about whether processes will operate in sequence or in parallel CPIT 250 System Analysis and Design

5. www.company.com Data Flow Diagram Data Flow Notations External Entity –An external entity can represent a human, system or subsystem. It is where certain data comes from (Source) or goes to (Destination). Remember: it named with a noun. Process –A process is a business activity or function where the manipulation and transformation of data takes place. –Remember: Must be numbered and labeled with a single action verb. CPIT 250 System Analysis and Design

6. www.company.com Data Flow Diagram Data Flow Notations Data Store –A data store represents the storage of data required and/or produced by the process. Data Flow –A data flow represents the flow of information, with its direction represented by an arrow CPIT 250 System Analysis and Design

7. www.company.com Data Flow Diagram Decomposition: is the process of representing the system in a hierarchy of DF diagrams –Child diagrams show a portion of the parent diagram in greater detail. CPIT 250 System Analysis and Design

8. www.company.com Developing Data Flow Diagram Step 1: –After determine the abstract scenario of your project, list all the business activities of the project –Use this list to determine the following: External Entities Data flows Processes Data stores CPIT 250 System Analysis and Design

9. www.company.com Developing Data Flow Diagram Step 2: –Note: DFD can be partitioned into levels. Each level has more information flow and data functional details than the previous level. –Highest level is Context Diagram. –In this step, you will begin to create a context diagram CPIT 250 System Analysis and Design Online Purchase System 0

10. www.company.com Developing Data Flow Diagram Some important points related to context diagram are: –It contains only ONE process represents the entire system. –It should contains all the external entities that may interact with the system. –Data arrows show input and output. –Data Stores NOT shown, as they are within the system. CPIT 250 System Analysis and Design

11. www.company.com Developing Data Flow Diagram Step 3: –Draw the next level which is Level – 0 diagram. CPIT 250 System Analysis and Design 3 2 1

12. www.company.com Developing Data Flow Diagram In the Level-0 Diagram you have to show, processes of the system (but keep them general), data stores are also shown in this level. Remember: It must balance with the context diagram. CPIT 250 System Analysis and Design

13. www.company.com Developing Data Flow Diagram Step 4: –In this stage, you will decompose level – 0 diagram to Level – 1 diagram –which shows how the system is divided into sub- systems (processes), each of which deals with one or more of the data flow to / from an external entity, and which together provide all of the functionality of the system as a whole. CPIT 250 System Analysis and Design

14. www.company.com Developing Data Flow Diagram CPIT 250 System Analysis and Design

15. www.company.com Example Patient Information System –Context Diagram CPIT 250 System Analysis and Design

16. www.company.com Example Patient Information System –Level – 0 Diagram CPIT 250 System Analysis and Design

17. www.company.com Example Patient Information System –Level – 0 Diagram CPIT 250 System Analysis and Design

18. www.company.com Example Patient Information System –Level – 1 Diagram CPIT 250 System Analysis and Design