University of Tennessee IM341 Spring 2014 Process Documentation Methods Authored by Dr. Hollander, with references to material presented in Hoffer, George, & Valacich’s Systems Analysis and Design texts, all rights reserved. 1PROCESS MODELING/DOCUMENTATION METHODS1 Organizations must document details about their processes or systems. In particular, there is a need for each organization to document - how data is captured, processed, and stored within its system, - how data flows within its system(s), and - how data flows to/from parties outside the organization or system boundaries. You could produce a voluminous written narrative describing the who, what, when, and where of a system or a business process, but there are alternative forms of documentation. Pages of narrative describing system processes and data/document flows can be succinctly summarized using graphical documentation methods. In this class, we will learn several documentation methods, including data flow diagramming, flowcharting, and E‐R diagramming (in a later module). I. DATA FLOW DIAGRAMS (DFD) Data flow diagramming symbols are used for a variety of system analysis purposes, including graphically displaying the movement of data through a process (between entities external to a system and any processes and data stores within a system). Logical data flow diagrams disregard physical attributes of a system such as organizational units, the computer on which the data are processed, and the media on which the data are stored. The movement of data across offices or departments within a particular system environment is not represented. DATA FLOW DIAGRAM SYMBOLS Two standard data flow diagramming symbol sets include those developed by Gane and Sarson and DeMarco and Yourdon. We show examples that illustrate use of each symbol set. 1 NOTE – It is assumed that the students will read and study this material prior to class discussions and assessment. This reference material is not duplicated in its entirety in the class module slides or class discussion. University of Tennessee IM341 Spring 2014 Process Documentation Methods Authored by Dr. Hollander, with references to material presented in Hoffer, George, & Valacich’s Systems Analysis and Design texts, all rights reserved. 2Process (Symbol A) Circles or rectangles with rounded corners are used to represent information processes that take data inflows and transform them to information outflows to be distributed or stored. The symbol contains two labels. The first label is a process number (explained in more detail later this document) and the second is a process name. Data Sources and Sinks (Destinations) (Symbol B) Squares represent the origin (source) of a data inflow and destination (sink) of an information outflow. The symbol is labeled with the name of the data source or sink/destination (e.g. Customer, Vendors, Government Agency, and other systems). The sources and sinks play an important role in the data flow diagram. The sources and sinks are external to (i.e. outside the scope of) the system represented on the diagram. They delineate the system boundaries. (Notice the word system, which is not the same as department or organization boundaries. Sources and sinks are external to the system.) Data Stores (Symbol C) Two parallel straight lines or a rectangle with the right vertical line missing are used to display a store or collection of data. Some people describe data stores as symbolizing data ‘at rest’. This symbol could represent data in a paper file or data in a computer file. A description of the data store contents is entered on the symbol. Data stores are used to denote stored data, and are necessary any time is stored (“at rest”). When output from one process “rests” before it is used as input to a second process, a data store symbol is necessary. Data Flow Lines (Symbol D) Data flow lines are lines with directional arrows that display the route of data inflow and outflow (data that is moving from one place to another). They can be straight or curved lines. The data flow is generally labeled with the name of the data (e.g. a customer order, a bill, a financial analysis) and the arrow indicates the direction of the data flow. University of Tennessee IM341 Spring 2014 Process Documentation Methods Authored by Dr. Hollander, with references to material presented in Hoffer, George, & Valacich’s Systems Analysis and Design texts, all rights reserved. 3The following diagram displays the basic elements of a DFD. The diagram shows a system with two processing steps, one data store, one data source and two data sinks. Data flows from a source external to the system being depicted into a process that is part of the system being depicted. The process depicted on the left takes this data flow and generates two outputs: one to a data sink and one into the process on the right. The process on the right receives two inputs and generates two outputs. One input is from the process on the left and one is from a data file. The two outputs flow into a data file and into a sink external to the scope of the system being depicted. DFD PREPARATION GUIDELINES AND RULES As with any documentation tool, there are some general guidelines that you should follow. Perhaps the best tip is to think in terms of input source, process, and output destination as you create your DFD. If you omit input, process, or output, your documentation is incomplete and flawed. The following data flow diagramming rules are recommended by Hoffner, George, and Valacich in their Systems Analysis and Design texts2 (great resources for those interested in learning about systems analysis and design in more depth). We will use these rules in this class. 2 Modern Systems Analysis and Design (6th Edition) by Jeffrey A. Hoffer, Joey F. George, Joseph S. Valacich, Prentice Hall 2011and Essentials of System Analysis and Design (5th Edition) by Joseph S. Valacich, Joey F. George, Jeffrey A. Hoffer, Prentice Hall 2011University of Tennessee IM341 Spring 2014 Process Documentation Methods Authored by Dr. Hollander, with references to material presented in Hoffer, George, & Valacich’s Systems Analysis and Design texts, all rights reserved. 4General Guidelines for Drawing a DFD 1. All processes should have unique names. If two data flow