1. System Analysis System Analysis - Mr. Ahmad Al-Ghoul System Analysis and Design

2. Avicenna System Analysis and Design System Analysis2 Learning Objectives Discuss how to create a set of data flow diagrams in a sequence, from general to specific Discuss how to create a set of data flow diagrams in a sequence, from general to specific discuss and draw the context diagram discuss and draw the context diagram Discuss and draw a Diagram 0 Discuss and draw a Diagram 0

3. Avicenna System Analysis and Design System Analysis3 Creating a Set of DFDs Create a graphical model of the information system based on your fact-finding results Create a graphical model of the information system based on your fact-finding results Create a set of DFDs by performing three main tasks Create a set of DFDs by performing three main tasks Step 1: Draw a context diagram, including all external entities and the major data flow to or from them Step 1: Draw a context diagram, including all external entities and the major data flow to or from them Step 2: Draw a diagram 0 DFD by analyzing the major activities within the context process Step 2: Draw a diagram 0 DFD by analyzing the major activities within the context process Include the external entities and major data stores Include the external entities and major data stores Step 3: Draw the lower-level diagrams for each complex process on Diagram 0 Step 3: Draw the lower-level diagrams for each complex process on Diagram 0

4. Avicenna System Analysis and Design System Analysis4 Creating a Set of DFDs The procedure for producing a DFD is to: The procedure for producing a DFD is to: identify and list external entities providing inputs to the system and receiving outputs from system identify and list external entities providing inputs to the system and receiving outputs from system identify and list inputs from external entities and outputs to external entities identify and list inputs from external entities and outputs to external entities create a context diagram with system at center and external entities sending and receiving data flows create a context diagram with system at center and external entities sending and receiving data flows identify the processes included within the system boundary identify the processes included within the system boundary identify the data connections between processes identify the data connections between processes verify all data flows have a source and destination verify all data flows have a source and destination verify data coming out of a data store goes as input to a process verify data coming out of a data store goes as input to a process review with "informed" review with "informed" explode and repeat above steps as needed explode and repeat above steps as needed

5. Avicenna System Analysis and Design System Analysis5 Creating a Set of DFDs Draw a Context Diagram Draw a Context Diagram Context Diagram is going to be the simplest DFD ( will have the minimum amount of symbols) Context Diagram is going to be the simplest DFD ( will have the minimum amount of symbols) First DFD in every business process First DFD in every business process Shows the context into which the business process fits Shows the context into which the business process fits Contains only one process, representing the entire system Contains only one process, representing the entire system The process is given the number zero The process is given the number zero All external entities are shown on the context diagram as well as major data flow to and from them All external entities are shown on the context diagram as well as major data flow to and from them The diagram does not contain any data stores The diagram does not contain any data stores

6. Avicenna System Analysis and Design System Analysis6 Creating a Set of DFDs Draw a Context Diagram Draw a Context Diagram Begin by reviewing the system requirements to identify all external data sources and destinations Begin by reviewing the system requirements to identify all external data sources and destinations Record the name of the entities and the name and content of the data flows, and the direction of the data flows Record the name of the entities and the name and content of the data flows, and the direction of the data flows

7. Avicenna System Analysis and Design System Analysis7 Creating a Set of DFDs We will use example of information system, the example is an order system that a company uses to enter orders and apply payments against a customer's balance We will use example of information system, the example is an order system that a company uses to enter orders and apply payments against a customer's balance External entities are External entities are CUSTOMER CUSTOMER WAREHOUSE WAREHOUSE SALES REP SALES REP BANK BANK ACCOUNTING ACCOUNTING Order information system consist of three main processes Order information system consist of three main processes FILL ORDER: which contains three sub processes, VERIFY ORDER, PREPARE REJECT NOTICE, and ASSEMBLE ORDER FILL ORDER: which contains three sub processes, VERIFY ORDER, PREPARE REJECT NOTICE, and ASSEMBLE ORDER CREATE INVOICE: no sub process CREATE INVOICE: no sub process APPLY PAYMENT: which contains four sub processes POST PAYMENT, DEPOSIT PAYMENT, PREPARE ACCOUNTING ENTRY, and PAY COMMISSION APPLY PAYMENT: which contains four sub processes POST PAYMENT, DEPOSIT PAYMENT, PREPARE ACCOUNTING ENTRY, and PAY COMMISSION

8. Avicenna System Analysis and Design System Analysis8 Creating a Set of DFDs Context diagram DFD for an order system. Notice that the ORDER SYSTEM process is at the center of diagram and five entities surround the process Notice that the ORDER SYSTEM process is at the center of diagram and five entities surround the process Three of the entities, SALES REP, BANK, and ACCOUNTING, have a single incoming data flows for COMMISSION, BANK DEPOSIT, and CASH RECEEIPTS Three of the entities, SALES REP, BANK, and ACCOUNTING, have a single incoming data flows for COMMISSION, BANK DEPOSIT, and CASH RECEEIPTS The WAREHOUSE entity has one incoming data flow PICKING LIST that is a report, that shows the items and their quantity, location, and sequence. The WAREHOUSE entity has one outgoing data flow, COMPLETED ORDER The WAREHOUSE entity has one incoming data flow PICKING LIST that is a report, that shows the items and their quantity, location, and sequence. The WAREHOUSE entity has one outgoing data flow, COMPLETED ORDER The CUSTMER entity has two outgoing data flows, ORDER and PAYMENT, and two incoming data flows, ORDER REJECT NOTICE and INVOICE The CUSTMER entity has two outgoing data flows, ORDER and PAYMENT, and two incoming data flows, ORDER REJECT NOTICE and INVOICE [1]

9. Avicenna System Analysis and Design System Analysis9 Creating a Set of DFDs Draw a Diagram 0 DFD Draw a Diagram 0 DFD The Context Diagram is a good starting point but it does not tell us much about the system, and that is where low level DFDs come into play. The Context Diagram is a good starting point but it does not tell us much about the system, and that is where low level DFDs come into play. In Context Diagram we had only one Process, we will break up this process into sub-processes. In Context Diagram we had only one Process, we will break up this process into sub-processes. The Diagram that will result from this breaking-up is called Diagram 0 (named so, because we are drawing a DFD that further explains the Process number "0"). The Diagram that will result from this breaking-up is called Diagram 0 (named so, because we are drawing a DFD that further explains the Process number "0"). How many sub-processes should we make out of Process 0? There is no rule It all depends on the system How many sub-processes should we make out of Process 0? There is no rule It all depends on the system

10. Avicenna System Analysis and Design System Analysis10 Creating a Set of DFDs Draw a Diagram 0 DFD Draw a Diagram 0 DFD Diagram 0 is the explosion of the context level diagram Diagram 0 is the explosion of the context level diagram Processes are numbered with an integer Processes are numbered with an integer The process numbers do not suggest that the processes are accomplished in a sequential order The process numbers do not suggest that the processes are accomplished in a sequential order Each process always is considered to be available, active, and awaiting data to be processed Each process always is considered to be available, active, and awaiting data to be processed The major data stores and all external entities are included on Diagram 0 The major data stores and all external entities are included on Diagram 0 A diverging data flow is a data flow in which the same data travels to two or more different locations A diverging data flow is a data flow in which the same data travels to two or more different locations If same data flows in both directions, you can use a double-headed arrow If same data flows in both directions, you can use a double-headed arrow To identify specific data flows into and out of a symbol, however, you use separate data flows symbols with single arrowheads To identify specific data flows into and out of a symbol, however, you use separate data flows symbols with single arrowheads

11. Avicenna System Analysis and Design System Analysis11 Creating a Set of DFDs Draw a Diagram 0 DFD Draw a Diagram 0 DFD If more detail were needed for any process in diagram 0, you would draw a level 1 diagrams If more detail were needed for any process in diagram 0, you would draw a level 1 diagrams If more detail needed for any process in level 1 diagrams, you would draw a level 2 diagrams, and so on If more detail needed for any process in level 1 diagrams, you would draw a level 2 diagrams, and so on Parent diagram Parent diagram Parent diagram Parent diagram The higher level diagram The higher level diagram Child diagram Child diagram Child diagram Child diagram The lower level diagram The lower level diagram Functional primitive Functional primitive Functional primitive Functional primitive Processes that do not create a child diagram Processes that do not create a child diagram You document the logic for a functional primitive in a process description in the data dictionary You document the logic for a functional primitive in a process description in the data dictionary Later, when the logical design is implemented as a physical system, programmers will transform each functional primitive into a unit of program code that carries out the required processing steps. Later, when the logical design is implemented as a physical system, programmers will transform each functional primitive into a unit of program code that carries out the required processing steps.

12. Avicenna System Analysis and Design System Analysis12 Creating a Set of DFDs diagram 0 for an order system. diagram 0 for an order system. Notice that process 0 on the order system’s context diagram is exploded to show three processes, FILL ORDER, CREATE INVOICE, and APPLY PAYMENT one data store, ACCOUNTS RECEIVABLE one data store, ACCOUNTS RECEIVABLE two new data flows, INVOICE DETAIL and PAYMENT DETAIL two new data flows, INVOICE DETAIL and PAYMENT DETAIL One diverging data flow INVOICE One diverging data flow INVOICE Depending on the processing logic Depending on the processing logic A CUSTOMER submit an ORDER, the FILL ORDER process either sends ORDER REJECT NOTICE to the customer entity or sends PICKING LIST to the WAREHOUSE entity A CUSTOMER submit an ORDER, the FILL ORDER process either sends ORDER REJECT NOTICE to the customer entity or sends PICKING LIST to the WAREHOUSE entity A COMPLETED ORDER from the WAREHOUSE entity is input to the CREATE INVOICE process, which output INVOICE to both CUSTOMER entity and the ACCOUNTS RECEIVABLE data store A COMPLETED ORDER from the WAREHOUSE entity is input to the CREATE INVOICE process, which output INVOICE to both CUSTOMER entity and the ACCOUNTS RECEIVABLE data store PAYMENT processed by APPLY PAYMENT process requires INVOICE DETAIL from ACCOUNTS RECEIVABLE data store a long with the PAYMENT. APPLY PAYMENT process outputs PAYMENT DETAIL to the ACCOUNTS RECEIVABLE data store and outputs COMMISSION to the SALES DEPT entity, BANK DEPOSIT to the BANK entity, and CASH REEIPTS ENTRY to ACCOUNTING entity PAYMENT processed by APPLY PAYMENT process requires INVOICE DETAIL from ACCOUNTS RECEIVABLE data store a long with the PAYMENT. APPLY PAYMENT process outputs PAYMENT DETAIL to the ACCOUNTS RECEIVABLE data store and outputs COMMISSION to the SALES DEPT entity, BANK DEPOSIT to the BANK entity, and CASH REEIPTS ENTRY to ACCOUNTING entity [1]

13. Avicenna System Analysis and Design System Analysis13 Creating a Set of DFDs Drawing Guidelines Drawing Guidelines 1. Draw the context diagram so that it fits on one page 2. Use the name of the information system as the process name in the context diagram 3. Use unique names within each set of symbols 4. Do not cross lines 5. Provide a unique name and reference number for each process 6. Obtain user input and feedback

14. Avicenna System Analysis and Design System Analysis14 Sequence Summary A set of DFDs is like a pyramid with the context diagram at the top A set of DFDs is like a pyramid with the context diagram at the top The context diagram represents the information system’s scope and its external connections but not its internal working The context diagram represents the information system’s scope and its external connections but not its internal working Diagram 0 displays the information system’s major processes, data stores, and data flows and its exploded version of the context diagram’s process symbol, which represents the entire information system Diagram 0 displays the information system’s major processes, data stores, and data flows and its exploded version of the context diagram’s process symbol, which represents the entire information system

15. Avicenna System Analysis and Design System Analysis15 Sequence Summary In this Sequence we have In this Sequence we have Discuss how to create a set of data flow diagrams in a sequence, from general to specific Discuss how to create a set of data flow diagrams in a sequence, from general to specific explained the context diagram explained the context diagram Explained the steps needed to draw the context diagram Explained the steps needed to draw the context diagram Explained a Diagram 0 Explained a Diagram 0 Explained how to draw a diagram 0 Explained how to draw a diagram 0

16. Avicenna System Analysis and Design System Analysis16 Reference [1] System Analysis and Design, Sixth Edition Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt, Authors: Gary B. Shelly, Thomas J. Cashman and Harry J. Rosenblatt, Publisher: SHELLY CASHMAN SEWIES. Publisher: SHELLY CASHMAN SEWIES. [2] system analysis and design, sixth edition Authors: Kenneth E. Kendall and Julie E. Kendall Authors: Kenneth E. Kendall and Julie E. Kendall Publisher: Prentice Hall Publisher: Prentice Hall [3] Modern Systems Analysis and Design Third Edition Authors: Jeffrey A. Hoffer, Joey F. George, Joseph S. Valacich Authors: Jeffrey A. Hoffer, Joey F. George, Joseph S. Valacich Publisher: prentice hall Publisher: prentice hall [4] System Analysis and Design, 3 rd Edition Authors: Dennis, Wixom, & Roth Authors: Dennis, Wixom, & Roth Publisher: John Wiley & sons Publisher: John Wiley & sons