Chapter 3 Systems Documentation Techniques Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 3-1

Learning Objectives  Prepare and use data flow diagrams to understand, evaluate, and document information systems.  Prepare and use flowcharts to understand, evaluate, and document information systems. Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 3-2

What is Documentation?  Set of documents and models  Narratives, data flow model, flowcharts, REA  Describe Who, What, Why, When & Where of Systems:  Input, Process, Storage, Output and Controls Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-3

Why should you learn documentation?  You need to be able to read documentation in all its forms: Narratives, diagrams, models.  You need the ability to evaluate the quality of systems, such as Internal Control based in part on documentation.  SAS 94: requires that independent auditors understand all internal control procedures  Documentation assists in auditor understanding and documentation of their understanding  Sarbanes-Oxley states that management:  Is responsible for Internal Control System  Is responsible for assessing the effectiveness of the IC System  Both management and external auditors need to document and test IC System Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-4

4 Benefits of Modeling  Uncover misunderstandings of system processes  Help communicate analyst system understanding to management/end users  Helps to take the system out of context  Eases the problem of thinking outside of the box

6 Fed Ex Process (Physical DFD) 6

Data Flow Diagrams  Graphically describes the flow of data within a system  Four Basic elements Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-7 Entity Process Data Flow Data Store

Entity  Represents a Source of Data or Input into the System and/or  Represents a Destination/Sink of Data or Output from the System  Entities exist outside of the system or process being modeled.  Label should be noun phrase (Person, Place or Thing) Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-8

Data Flows  Movement of Data between:  Entities (Sources and/or Destinations)  Processes  Data Stores  Label should describe the information moving (Noun Phrase) Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-9

Process  Represents the Transformation of Data  Label should describe the transformation (Verb) Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-10

Data Store  Represents Data at Rest  Label should describe the data being stored (noun phrase)  Or Activity # from E&A table Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-11

Data Flow Diagram Levels  Context  Highest Level (Most General)  Purpose: Show Inputs & Outputs into/from System  Characteristics: One Process Symbol only, No Data Stores  Level-0  Purpose: Show all major activity steps of a system  Characteristics: Processes are labeled 1.0, 2.0, etc. Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-12

15 DFD Levels  DFD models are organized in a series of levels so that each level provides successively more detail about a portion of the level above  Top Level: Context Diagram  consists of only one bubble representing the entire system  the data flows show the interfaces between the system and the external entities  Successive Levels:  Figure/Level-0  highest-level view of the major functions within the system  the major interfaces between those functions  Level-1 ...  Level n

16 How Many Levels should you have?  each DFD figure should have no more than half a dozen bubbles and related stores*.  Simple Systems  2-3 Levels  Medium Sized System  3-6 Levels  Large System  5-8 Levels * This is just a guideline not a rule

Context Diagram Must have at least one input and one output Does not include Data Stores Represents all the Inputs into and Outputs from the system Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-15

Level - 0 Represents each main activity of process being modeled Process numbering indicates when each activity occurs Should include data stores Number of Inputs and Outputs must be the same as in the Context Diagram Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall

DFD Creation Guidelines  Understand the System  Ignore Certain Aspects of the System  Determine System Boundaries  Develop a Context DFD  Identify Data Flows  Group Data Flows  Number each Process  Identify transformational processes  Group transformational processes  Identify all Data Stores  Identify All Sources and Destinations  Label all DFD elements  Subdivide DFD Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-17

30 Three Basic Illegal Data Flows Black Hole Miracle Gray Hole EntityName FileName Employee EmployeeFile

31 Other Illegal Flows EmployeeFile D1 OrderFile D2 Data Must Be Connected to a Process Employee No Bi-Directional Flows Customer CustFile D1

32 One Final Illegal Flow Data Cannot Flow Directly Back Into The Process It Left

33 A Debate Which is Right?

35 Preparing Data Flow Diagrams  Read narrative carefully - number lines and paragraphs in text  Prepare table of entities and activities (Will learn about this next class)  Include on the systems documentation all (and only) activities and entities described in the systems narrative - no more, no less.  When multiple entities operate identically, depict only one to represent all.  Draw context diagram - use DFD guidelines

14 DFD Guidelines 1. Choose meaningful names for processes, flows, stores, and terminators.  Entity – Noun  Process – Verb  Data Flow – Noun  Data Store - Noun 2. Number the processes.  Order has meaning, chronological order in which activities occur. 3. Redraw the DFD as many times as necessary for esthetics. 4. Avoid overly complex DFDs.  If it looks complex it’s probably done wrong; you’re probably modeling multiple processes rather than only one. 5. Make sure the DFD is internally consistent and consistent with any associated DFDs (ie Balanced).

40 DFD Guidelines (Level-0 and higher)  6. Group activities if they occur in the same place and at the same time.  7. Group activities if they occur at the same time but in different places.  8. Group activities that seem to be logically related.  9. To make the DFD readable, use between five and seven bubbles.  10. On a logical DFD, data flows cannot go from higher- to lower-numbered bubbles.

Flowcharts  Use symbols to logically depict transaction processing and the flow of data through a system.  Using a pictorial representation is easier to understand and explain vs. a detailed narrative. Copyright 2012 Pearson Education, Inc. publishing as Prentice Hall 25

Flowchart Symbol Categories  Input/Output  Processing  Storage  Miscellaneous Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-26

Flow Chart Symbol Categories  (cont’d) Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall

Types of Flowcharts  Document  Illustrates the flow of documents through an organization.  Useful for analyzing Internal Control procedures.  System  Logical representation of System Inputs, Processes and Outputs  Useful in Systems Analysis and Design  Program  Represent the logical sequence of program logic Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-28

Document Flowchart Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-29

System Flowchart Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-30

Program Flowchart Copyright 2012 © Pearson Education, Inc. publishing as Prentice Hall 3-31

50 Preparing Systems Flowcharts  1. Divide the flowchart into columns; one column for each internal entity and one for each external entity. Label each column.  2. Flowchart columns should be laid out so that the flowchart activities flow from left to right, but you should locate columns so as to minimize crossed lines and connectors.

51 System flowcharting guidelines (cont.)  3. Flowchart logic should flow from top to bottom and from left to right. For clarity, put arrows on all flow lines.  4. Keep the flowchart on one page. If you can’t, use multiple pages and connect the pages with off-page connectors. Computerized flowcharting packages will print your flowcharts only on paper that will fit in your printer!

52

53 System flowcharting guidelines (cont.)  5. Within each column, there must be at least one manual process, keying operation, or data store between documents. That is, do not directly connect documents within the same column.  6. When crossing organizational lines (one column to another), show a document at both ends of the flow line unless the connection is so short that the intent is unambiguous.

54 System flowcharting guidelines (cont.)  7. Documents or reports printed in a computer facility should be shown in that facility’s column first. You can then show the document or report going to the destination unit.  8. Documents or reports printed by a centralized computer facility on equipment located in another organizational unit ( warehouse, shipping dept.) should not be shown within the computer facility.

55 System flowcharting guidelines (cont.)  9. Processing within an organizational unit on devices such as a PC or computerized cash register should be shown within the unit or as a separate column next to that unit, but not in the central computer facility column.  10. Sequential processing steps (computerized or manual) with no delay between them (and resulting from the same input) can be shown as one process or as a sequence of processes.

56 System flowcharting guidelines (cont.)  11. The only way into a computer data storage unit is through a computer processing rectangle.  12. A manual process is not needed to show the sending of a document. The sending of the document should be apparent from the movement of the document itself.  13. Do not use a manual process to file a document. Just show the document going in to a file.