1. Documenting Information Systems

2. Learning Objectives To read and evaluate data flow diagrams To read and evaluate systems flowcharts. To prepare data flow diagrams from a narrative. To prepare systems flowcharts from a narrative. Documenting Information Systems

3. 3 Documenting Processes on the AIS Wheel Process documentation is a important skill in accounting You will learn that data flow diagrams portray a business processes’ activities, stores of data, and flows of data among those elements. Systems flowcharts, on the other hand, present a comprehensive picture of the management, operations, information systems, and process controls embodied in business processes.

4. 4 Basic DFD Symbols

5. 5 CONTEXT DIAGRAM

6. 6 Physical DFD A physical data flow diagram is a graphical representation of a system showing the system’s internal and external entities, and the flows of data into and out of these entities. –A physical DFD specifies where, how, and by whom a system’s processes are accomplished. –A physical DFD does not tell us what is being accomplished. –In the following slide, we see where the cash goes and how the cash receipts data are captured (that is, on the register tape), but we don’t know exactly what was done by the sales clerk.

7. 7 Physical DFD

8. 8 Logical DFD A logical data flow diagram is a graphical representation of a system showing the system’s processes (as bubbles), data stores, and the flows of data into and out of the processes and data stores. –We use a logical DFD to document information systems because we can represent the logical nature of a system— what tasks the system is doing— without having to specify how, where, or by whom the tasks are accomplished. –The advantage of a logical DFD (versus a physical DFD) is that we can concentrate on the functions that a system performs. –So, a logical DFD portrays a system’s activities, whereas a physical DFD depicts a system’s infrastructure. –We need both pictures to understand a system completely.

9. 9 Logical DFD

10. 10 Balanced DFDs The next slide depicts “balanced” data flow diagrams. Balanced DFDs exist when the external data flows are equivalent. DFD (a) is a context diagram and (b) is an “explosion” of it into a level 0 logical DFD. DFD (c), (d) and (e) are “explosions” of the logical level 0 DFD, and so on.

11. 11 Balanced DFDs

12. 12 Standard Flowchart Symbols

13. 13 Common system flowcharting routines The following slides show several common ways of showing processing using system flowcharting. Pay particular attention to the way the columns are set up to communicate the flow of activities between processing entities.

14. 14 Enter document into computer via keyboard, edit input, record input

15. 15 User queries the computer Update sequential data store

16. 16 PREPARATION AND LATER MANUAL RECONCILIATION OF CONTROL TOTALS

17. 17 KEY AND KEY VERIFY INPUTS

18. 18 Enter document into computer using a scanner

19. 19 Enter document into computer using scanner & manual keying

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21. 21 Documenting Enterprise Systems Moving from a file-based system to an enterprise database changes the system flowchart –An enterprise database replaces transaction and master data –Other flows may change depending on the system implementation

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