Flowchart and Data Flow Diagrams Supplemental A Flowchart and Data Flow Diagrams

Purpose and Description Flowchart are used to describe an entire information system or some portion of it. System flowcharts are used to illustrate the entire information system The different types of flowcharts are as follows Systems flowcharts chow the entire system configuration, including the documents data flows, and processes of a system. Document/procedure flowcharts show the creation, flow and destination of documents within a system and the procedures performed on them. Hardware flowcharts show the hardware configuration of a system. Program flowcharts show the logic and processing steps of a computer program.

The Basic Elements of Systems/Document Flowcharts Document flowcharts consists of three simple graphical elements that can be combined to represent various types of information flows and processes: Symbols Flow lines Areas of responsibility Flowcharting symbols and methods can vary widely across professions and organizations. There is no one set of generally accepted flowcharting principles and symbols.

EXHIBIT A-1 Document Flow in a Manual Accounting System subsidiary ledger Prepare Sales invoice 3 2 Source 1 Documents N Employee Involved In the Transaction Record transaction journal entry Record 3 Document Investors/creditors Transaction journal General Ledger Post Journal entries to ledgers Financial statements Trial balance Accounting Department N = Numeric Adjust and Close Ledger Financial Statement Customer

Flowcharting element 1 : symbols A variety of symbols are used to represesnt the physical aspects of the document/data flows and processes of an information system. Input and output: documents The documents symbol is used for all types of paper source documents that are processes by the system.

EXHIBIT A-2 Sales/Collection Document Flowchart 3 2 Start Prepare Sales invoice Check Customer Credit Sales 1 N Sales Clerk From Payment Endorse check and prepare remittance advice Remittance advice 1 Record transaction and update ledger Transaction journal Accounts receivable ledger Cash Receipts Clerk Account Receivable Clerk N = Numeric

EXHIBIT A-3 Flowchart Symbols: Documents 4 3 Invoice 2 Shipping 1 receipt Sales Sales 3 (A) Single Document (B) Non processed Documents (C) Overlapping symbols Same documents (D) Two overlapping Symbols, same documents (E) Two overlapping Symbols, Different documents

EXHIBIT A-4 Flowchart Symbols Online Manual Device (B) Terminal Display (C) I/O (Input/Output) (D) Manual process (E) Online Computer A N Permanent File Temporary file (F) Offline or Non computer (G) Offline Paper (H) data storage (I) Disk (J) Magnetic tape

EXHIBIT A-5 More Flowchart Symbols From bank To customer Start 1 Indicates the flow will Continue at on-page connector 1 Indicates where the flow continues from on-page connector 1 (C) On-page connectors (A) Enter/Exit System (B) (or end) process (E) Annotation (F) Decision (G) Calculator Register tape (H) Physical Object (I) Flow Lines (J) Communication Link p.4 On page 2: To page 4 Connector 1 On page 4: p.2 From page 4 (D) OFF-page

Summary The flowchart is one of the easier types of documentation for information customers and management to understand. Often auditors use system, document and procedure flowcharts to understand business and system controls in an environment. The primary weakness of the flowchart is that it is tied to physical information flows and system characteristic that hide the procedural essence of the system. Data flow diagrams are a useful tool for documenting the conceptual aspects of an information system.

DATA FLOW DIAGRAMS (DFD) A second documentation tool is the data flow diagram (DFD). Data Flow Diagramming symbols are used for a variety of system analysis purposes, including graphically displaying the logical flows of data through a process. Unlike flowcharts, which represent the physical components of an information system, data flow diagrams can provide a more conceptual, nonphysical display to the movement of a data through a system. Data flow diagrams disregard such things as organizational units, the computer on which the data are processed, and the media on which the data are stored.

Data Flow Diagram Symbols Data Flow diagrams include four symbols : process, data inflow sources and outflow sinks (destinations), data stores and data flow lines. Like flowcharting, there are variations on some of the symbols.

EXHIBIT A-6 Data Flow Diagram Symbol Process (B) Sources/Sinks (C) Data Store (D) Data Flow Lines DeMarco and Yourdan symbols Gane and Sarson symbols

EXHIBIT A-7 Data Flow Diagramming Rules Rule Number 4 5 7 8 9 13 11 14 15 16 Incorrect Correct A C B J. Hoffner, J. George, and J. Valacich, Modern System Analysis and Design (Reading, MA: Benjamin/Cummings, 1996), p. 31

EXHIBIT A-8 Context Diagram Example Levels of Data Flow Diagrams The highest level of data flow diagrams is the context diagram EXHIBIT A-8 Context Diagram Example Customers Sales/Collection System Decision Makers Order Bill Payments Desired Information

EXHIBIT A-9 Level Zero DFD Example Customers 2.0 Process shipments to customers Decision Makers Order Bill Payments Desired Information 1.0 orders 3.0 from Due data Subsequent level DVDs The process identified in the context diagram is divided into the more detailed processes performed within the system

EXHIBIT A-10 Level –One DFD Example Approved order Order data 1.1 Approve and record customer order data 1.2 Generate information about orders Customer order data Order Shipping Request data Approved order Order data Desired Information

EXHIBIT A-11 Level –Two DFD Example data 1.1.1 Receive from 1.1.2 1.1.4 Record order data 1.1.2 Check customer status Customer data Order Approved order Inventory availability 1.1.1 Receive from 1.1.3 inventory Customer credit status data

Example Data Flow Diagram EXHIBIT A-12 Comparative Example-Version 1 N 2 Example Data Flow Diagram Review time cards Time 1 Cards Example Flowchart A = Alphabetic A Record Wages Employee Earning Records Factory Supervisor Review Time Employee earnings records Time card file (alpha) supervisor Accounting payroll clerk Reviewed Time cards

Example Data Flow Diagram EXHIBIT A-12 Comparative Example-Version 2 N 2 Example Data Flow Diagram Review time cards Time 1 Cards Example Flowchart A = Alphabetic Factory Supervisor Review Time Employee earnings records Time card file (alpha) supervisor Accounting payroll clerk Reviewed Time cards Key in time cards Record wages A Earning master file

Example Data Flow Diagram EXHIBIT A-14 Comparative Example-Version 3 N 2 Example Data Flow Diagram Review time cards Time 1 Cards Example Flowchart A = Alphabetic Factory Supervisor Review Time Employee earnings records Time card file (alpha) supervisor Accounting payroll clerk Reviewed Time cards Key in time cards Record wages A Employee Earning master file