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Systems Development and Documentation Techniques

Introduction: S

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Systems Development and Documentation Techniques

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    1. Systems Development and Documentation Techniques Chapter 3 2-1 ©2003 Prentice Hall Business Publishing, Accounting Information Systems, 9/e, Romney/Steinbart

    2. Introduction: S&S, Inc. S&S has opened and growing quickly. Ashton realizes he needs the help of a systems consulting firm (CA) to improve their AIS. Ashton finds that they need better documentation of the business activities to proceed. 2-2

    3. Introduction: S&S, Inc. Ashton was left with the following assignment: What should be documented so the S&S AIS is easy to understand and evaluate? What development tools and techniques should S&S use to design its new AIS? 2-3

    4. Learning Objectives What is the purpose of documentation? Why do accountants need to understand documentation? What documentation techniques are used in accounting systems? 2-4

    5. Learning Objectives Understand the following documentation tools Data Flow Diagrams (DFD) Document flowchart System Flowchart Program Flowchart 2-5

    6. Documentation Diagrams with written descriptions are the most popular and clear way of explaining how a system works. Documentation ‘tools’ will also be discussed. 2-6

    7. Documentation Includes the following tools: Descriptions Flowcharts Diagrams Anything that will help explain how a system works 2-7

    8. Documentation How is documentation used? 2-8

    9. Documentation How is documentation used: Read documentation Evaluate internal controls Prepare documentation 2-9

    10. Data Flow Diagrams (DFD) What is this? Why do we use it? 2-10

    11. Data Flow Diagrams (DFD) It is better to see pictures than words. It is easier to analyze all the inputs and outputs. 2-11

    12. Data Flow Diagrams (DFD) They show: Where data comes from How it flows The processes performed on it Where it goes 2-12

    13. Data Flow Diagrams (DFD) They are used to: Document existing systems Plan and design new systems 2-13

    14. Data Flow Diagrams (DFD) What do they look like? What type of transaction is this? 2-14

    15. Data Flow Diagrams (DFD) They consist of 4 parts: Data sources and destinations Data flows Transformation processes Data stores 2-15

    16. Data Flow Diagrams (DFD) Data sources and destinations Appear as squares Represent organizations or individuals that send or receive data used or produced by the system 2-16

    17. Data Flow Diagrams (DFD) 2-17

    18. Data Flow Diagrams (DFD) Data flows Appear as arrows Represent the flow of data between sources and destinations, processes, and data stores 2-18

    19. Data Flow Diagrams (DFD) 2-19

    20. Data Flow Diagrams (DFD) Transformation processes Appear as circles Represent the transformation of data 2-20

    21. Data Flow Diagrams (DFD) 2-21

    22. Data Flow Diagrams (DFD) Data stores Appear as two horizontal lines Represent a temporary or permanent store of data 2-22

    23. Data Flow Diagrams (DFD) DFD sub-systems (subdividing the DFD): Often a company’s structure is complicated, so it may not be possible to use just one DFD Or we may want to look at an activity in greater detail. 2-23

    24. Data Flow Diagrams (DFD) DFD sub-systems (subdividing the DFD): The normal DFD is called the context diagram. This is a summary For more detail, we can look at the ‘subdivided’ DFD. 2-24

    25. Data Flow Diagrams (DFD) DFD sub-systems (subdividing the DFD): Example: What would the DFD for a simple payroll processing system look like? 2-25

    26. Data Flow Diagrams (DFD) DFD sub-systems (subdividing the DFD): Example: What would the subdivided DFD look like? 2-26

    27. Data Flow Diagrams (DFD) 2-27

    28. Data Flow Diagrams (DFD) 2-28

    29. Data Flow Diagrams (DFD) Leveled DFD’s: 2-29

    30. Data Flow Diagrams (DFD) Leveled DFD’s: 2-30

    31. Data Flow Diagrams (DFD) Leveled DFD’s: 2-31

    32. Data Flow Diagrams (DFD) Leveled DFD’s: 2-32

    33. Data Flow Diagrams (DFD) Leveled DFD’s: 2-33

    34. Data Flow Diagrams (DFD) Leveled DFD’s: 2-34

    35. Data Flow Diagrams (DFD) Constructing DFD guidelines: Number the processes be consistent in numbering numbering scheme has nothing to do with sequence of execution. It should be served as a convenient way of referring to the processes. More importantly, the numbers become the basis for a hierarchical numbering scheme in leveled DFDs. 2-35

    36. Data Flow Diagrams (DFD) Constructing DFD guidelines: Avoid overly complex DFDs DFD should be readily understood, easily absorbed, and pleasing to the eye do not create a DFD with too many processes (usually 3-8 processes in a level), flows, stores, and terminators. 2-36

    37. Data Flow Diagrams (DFD) Constructing DFD guidelines: Redraw DFDs as many times as necessary redrawn again and again until it is (1) technically correct, (2) acceptable to the user, and (3) neatly enough. Develop an accurate, consistent, esthetically pleasing model. 2-37

    38. Data Flow Diagrams (DFD) Constructing DFD guidelines: Make sure DFD’s are logically consistent: What is the problem here? 2-38

    39. Data Flow Diagrams (DFD) Re-create the DFD for a customer payment process: 2-39

    40. Data Flow Diagrams (DFD) Customer Payment Process 2-40

    41. Data Flow Diagrams (DFD) Student registration system 2-41

    42. Data Flow Diagrams (DFD) Student registration system Level-0 diagram 2-42

    43. Data Flow Diagrams (DFD) Student registration system Level-0 diagram The college requires that each student complete a registration request form the system checks the student transcript to ensure that he or she has completed the course prerequisites The report back to the student shows the result of registration processing: If the student owes fees, a bill is sent and the registration is rejected. If the class is full, the student is told with a “course closed” notice. If a student is accepted into a class, they are notified Course enrollment reports are prepared for the instructors. 2-43

    44. Data Flow Diagrams (DFD) Example: Payroll process When employees are hired, they complete a new employee form. When a change to an employee’s payroll status occurs, such as a raise or a change in the number of exemptions, human resources completes an employee change form. A copy of these forms is sent to payroll. These forms are used to create or update the records in the employee/payroll file and are then stored in the file. Employee records are stored alphabetically. 2-44

    45. Data Flow Diagrams (DFD) Example: Payroll process 2-45

    46. Data Flow Diagrams (DFD) Example: Payroll process 2-46

    47. Data Flow Diagrams (DFD) Context diagram for S&S Payroll 2-47

    48. Data Flow Diagrams (DFD) S&S Payroll Level-0 diagram 2-48

    49. Data Flow Diagrams (DFD) Context diagram for a food ordering system 2-49

    50. Data Flow Diagrams (DFD) Level-0 DFD for a food ordering system 2-50

    51. Data Flow Diagrams (DFD) 2-51

    52. Data Flow Diagrams (DFD) 2-52

    53. Data Flow Diagrams (DFD) 2-53

    54. Data Flow Diagrams (DFD) 2-54

    55. Data Flow Diagrams (DFD) Constructing a context diagram identify and list data sources and destinations identify and list inputs to and outputs from data sources and destinations create context diagram 2-55

    56. Data Flow Diagrams (DFD) Drawing a Level-0 Diagram list the major data stores list major business steps draw a segment for each business step assemble into single DFD re-organize until satisfied number processes 2-56

    57. Travel Agency Example A travel agency arranges holidays for customers. Bookings are made directly by customers. When a customer makes an approach, the reservations clerk selects appropriate flight details and hotel details from lists which are regularly updated. The details are entered onto a Provisional Booking file. The customer must confirm this booking within three days by sending a deposit of 10% of the costs. On receipt of the deposit, Reservations transfer the details from the Provisional Bookings file to the Full Bookings file. Four weeks before the flight is due, Accounts send an invoice to the customer for the remaining costs. Accounts notify Customer services when the full payment is received, and Customer Services then send tickets and joining instructions to the customer. 2-57

    58. Travel Agency Example Context Level Diagram 2-58

    59. Travel Agency Example 2-59

    60. Travel Agency Example 2-60

    61. Flowcharts Definition – a tool used to represent part of an information system in a clear, concise, and logical manner 2-61

    62. Flowcharts Types Document flowchart - depicts flow of documents & information between areas of responsibility within an organization System flowchart – depicts how data are captured & input into the system, the processing performed on the data, and the information output by the AIS Program flowchart – indicates the sequence of logical operations performed by the computer when executing a program 2-62

    63. Flowcharts Differences Between DFDs and Flowcharts: DFDs emphasize the flow of data and what is happening in a system, whereas a flowchart emphasizes the flow of documents or records containing data. A DFD represents the logical flow of data, whereas a flowchart represents the physical flow of data. 2-63

    64. Flowcharts Differences Between DFDs and Flowcharts: Flowcharts are used primarily to document existing systems and are concerned with the physical aspects of the input, processing and storage of the data. DFDs, in contrast, are primarily used in the design of new systems and do not concern themselves with the physical devices used to process, store, and transform data. 2-64

    65. Flowcharts Differences Between DFDs and Flowcharts: DFDs make use of only four symbols. Flowcharts use many symbols and thus can show more detail. 2-65

    66. Flowcharts EXAMPLE: The registrar’s office of a small college receives paper enrollment forms from students. They sort these records alphabetically and then update the student record file to show the new classes. They also prepare class lists from the same data. The sorted enrollment forms are forwarded to the bursar’s office for billing purposes. Class lists are mailed to faculty members. 2-66

    67. Flowcharts 2-67

    68. Flowcharts 2-68

    69. Flowcharts 2-69

    70. 2-70

    71. 2-71

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