Systems Documentation Techniques PDF

Systems Documentation Techniques Chapter 3 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....

Systems Documentation Techniques Chapter 3 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. 3-2 What Is Documentation?  Set of documents and models  Narratives, data flow models, flowcharts  Describe who, what, why, when, and where of systems:  Input (data entry),  process,  storage,  output, and  controls 3-3 Data Flow Diagrams  A data flow diagram (DFD) graphically describes the flow of data within an organization.  It is used to document existing systems and to plan and design new ones.  There is no ideal way to develop a DFD. 3-4 Data Flow Diagrams and Symbols  A data flow diagram (DFD) is composed of the following four basic elements: 1 Data sources and destinations 2 Data flows 3 Transformation processes 4 Data stores 3-5  DATA FLOW DIAGRAMS  Data sources and destinations  Appear as squares  Represent organizations or individuals that send or receive data used or produced by the system Data flows – Appear as arrows – Represent the flow of data between sources and destinations, processes, and data stores 3-6  DATA FLOW DIAGRAMS  Transformation Processes  Appear as circles  Represent the transformation of data Data stores – Appear as two horizontal lines – Represent a temporary or permanent repository of data 3-7  DATA FLOW DIAGRAMS  Data dictionary:  The data dictionary contains a description of all data elements, data stores, and data flows in a system. The highest level of DFD is called a context diagram. – It provides a summary-level view of the system. – It depicts a data processing system and the external entities that are: Sources of its input Destinations of its output 3-8  Data Flow Diagrams Data Data flow (B) Process Data flow (D) source (C) (A) Data flow (E) Data destination (J) 3-9 Data Flow Diagrams Data store (H) Data flow (G) Data flow (D) Data flow (I) Data Process destination (F) (K) 3-10  Data Flow Diagrams Customer Remittance payment (B) data (D) Customer Process (A) payment (C) Deposit (E) Bank (J) 3-11 Data Flow Diagrams Accounts receivable (H) (G) Remittance data Receivables (D) information (I) Update Credit receivables manager (F) (K) 3-12 DFD Creation Guidelines  Understand the system  Identify transformational processes  Ignore certain aspects of the system  Group transformational processes  Determine system boundaries  Identify all data stores  Develop a context DFD  Identify all sources and destinations  Identify data flows  Label all DFD elements  Group data flows  Subdivide DFD  Number each process 3-13  Flowcharts  A flowchart is an analytical technique used to describe some aspect of an information system in a clear, concise, and logical manner.  Flowcharts use a standard set of symbols to pictorially describe transaction processing procedures.  Flowcharting symbols can be divided into the following four categories: 1 Input/output symbols 2 Processing symbols 3 Storage symbols 4 Flow and miscellaneous symbols 3-14 Flowchart Symbol Categories 3-15  Flow Chart Symbol Categories 3-16 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 3-17 What are Document Flowcharts?  A document flowchart illustrates the flow of documents and information between areas of responsibility within an organization.  A document flowchart is particularly useful in analyzing the adequacy of control procedures.  Flowcharts that describe and evaluate internal controls are often referred to as internal control flowcharts. 3-18 Document Flowchart 3-19  Document Flowchart (cont’d) Copyright © 2012 Pearson Education, Inc. publishing as Prentice Hall 3-20 What are System Flowcharts?  System flowcharts depict the relationship among inputs, processing, and output for a system.  A system flowchart begins by identifying both the inputs that enter the system and their origins.  The input is followed by the processing portion of the flowchart.  The resulting new information is the output component.  System flowcharts are an important tool of system analysis, design, and evaluation. 3-21 System Flowchart 3-22 What are Program Flowcharts?  A program flowchart describes the sequence of logical operations performed in a computer program.  A flow line connects the symbols and indicates the sequence of operations.  The processing symbol represents a data movement or arithmetic calculation.  The input/output symbol represents either reading of input or writing of output.  The decision symbol represents a comparison of one or more variables and the transfer of flow to alternative logic paths.  All points where the flow begins or ends are represented by the terminal symbol. 3-23 Program Flowchart 3-24 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.  Flowcharts are used primarily to document existing systems. DFDs, in contrast, are primarily used in the design of new systems.  DFDs make use of only four symbols. Flowcharts use many symbols and thus can show more detail. 3-25  Summary  Reasons to document an AIS are: to explain how system works, to document a business’s processes, to train others, to design a new system, to control system development and maintenance costs, to standardize communications among system designers, to provide information to auditors, to establish employee accountability for specific tasks or procedures.  A document flowchart provides an overview of where documents are created, sent, reviewed, and stored, and what activities they trigger.  A system flowchart indicates what processing steps and files are used and when, and provides an overview of the entire system. 3-26  Summary  Data flow diagram provide both a physical and logical view of a system but concentrate more on the flow and transformation of data than on the physical devices or timing of inputs, processing, or outputs.  Two additional documentation tools are program flowcharts and decision tables.  Accountants do not need to be programmers to evaluate or design an accounting information system, but they should understand in general terms how these tools work. 3-27