Chapter 4: documenting information systems

Chapter 4: documenting information systems
ACCOUNTING INFORMATION SYSTEMS 11e Gelinas ►Dull ► Wheeler ► HILL © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Synopsis This chapter covers: Data Flow Diagrams. Flowcharts.
© 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Reading Systems Documentation
Two types of systems documentation: Data flow diagrams. Systems flowcharts. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Reading Data Flow Diagrams (slide 1 of 10)
Data flow diagrams (DFDs): Show business processes, flows of data within those processes, and the sources and storage of the data required for the process. Depict systems components. Data flows among components, and the sources. Destinations. Storage of data. Use a limited number of symbols. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Context Diagram Context diagram: Least detailed picture of a system that defines the process being documented and shows the data flows into and out of the process to external entities. External entities: Those entities (i.e., persons, places, or things) outside the system that send data to, or receive data from, the system. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Physical Data Flow Diagram Physical data flow diagram (DFD): Graphical representation of a system showing the system’s internal and external entities, and the flows of data into and out of these entities. Specifies where, how, and by whom a system’s processes are accomplished. Internal entity: An entity within the system that transforms data. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Logical Data Flow Diagram Logical data flow diagram (DFD): Graphical representation of a system showing the system’s processes (as bubbles), data stores, and the flows of data into and out of the processes and data stores. Specifies what activities the system is performing. Logical DFDs portray a system’s activities. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Balanced: When two DFDs have equivalent external data flows. Only balanced sets of DFDs (i.e., a context diagram, a logical DFD, and a physical DFD) are correct. Top-down partitioning: The successive subdividing (exploding) of logical DFDs. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Reading Systems Flowcharts (SLIDE 1 OF 10)
Systems flowchart: Graphical representation of a business process, including information processes, as well as the related operations processes (people, equipment, organization, and work activities). Presents a logical and physical rendering of the who, what, how, and where of information and operations processes. Depicts the sequence of activities performed as business events flow through the process. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Common Systems Flowcharting Routines The following slides show several common ways of showing processing using system flowcharting. Note the way the columns are set up to communicate the flow of activities between processing entities. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Enter document into computer via keyboard, edit input, record input. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

User queries the computer. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Update data store. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Key and key verify data. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Enter document via scanning. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Enter journal in manual accounting system. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Pick and ship goods. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Preparing Data Flow Diagrams (SLIDE 1 of 3)
Analyze narrative. Create a table of entities and activities. An activity is any action being performed by an internal or external entity. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

The Narrative © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Table of Entities and Activities Activity: Actions related to data (send data, transform data, file or store data, retrieve data from storage, or receive data). Operations process activities include picking goods, inspecting goods at a receiving dock, or counting cash. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Drawing the Context Diagram (SLIDE 1 OF 6)

Information processing activities: Retrieve data from storage, transform data, or file data. DFD guidelines: Include within the system context (bubble) any entity that performs one or more information processing activities. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

For now, include only normal processing routines (not exception routines or error routines) on context diagrams, physical DFDs, and logical level 0 DFDs. Include in the process documentation all (and only) activities and entities described in the systems narrative. When multiple entities operate identically, depict only one to represent all. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Drawing the Current Physical Data Flow Diagram For clarity, draw a data flow for each flow into and out of a data store. Label each flow with the activity number that gives rise to the flow or with a description of the flow. If a data store is logically necessary, include a data store in the diagrams, even if it not mentioned in the narrative. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Drawing the Current Logical Data Flow Diagram (SLIDE 1 OF 5)
Group activities if they occur in the same place and at the same time. Group activities if they occur at the same time but in different places. Group activities that seem to be logically related. To make the DFD readable, use between five and seven bubbles. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Summary of Drawing Data Flow Diagrams A data flow should go to an operations entity square when only operations process functions are to be performed by that entity. A data flow should enter an entity bubble if the operations process entity is to perform an information processing activity. On a physical DFD, reading computer data stores and writing to computer data stores must go through a computer bubble. On a logical DFD, data flows cannot go from higher- to lower- numbered bubbles. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Processes called exception routines or error routines handle required actions for out-of-the-ordinary (exceptional) or erroneous events data. Documented below the level 0 DFD with reject stubs that indicate exceptional processing must be performed. A reject stub is a data flow assigned the label “Reject” that leaves a bubble but does not go to any other bubble or data store. Shown only in lower-level diagrams. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Preparing Systems Flowcharts (SLIDE 1 OF 5)
Divide the flowchart into columns; one column for each internal entity and one for each external entity. Label each column. Flowchart columns should be laid out so that the flowchart activities flow from left to right. Minimize crossed lines and connectors. Flowchart logic should flow from top to bottom and from left to right. For clarity, put arrows on all flow lines. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Keep the flowchart on one page, if possible. Use off-page connectors if multiple pages are required. Within each column, there must be at least one manual process, keying operation, or data store between documents. When crossing organizational lines show a document at both ends of the flow line unless the connection is so short that the intent is unambiguous. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

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. Documents or reports printed by a centralized computer facility on equipment located in another organizational unit should not be shown within the computer facility. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Processing within an organizational unit on devices such as a PC, laptop, 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. Sequential processing steps with no delay between them (and resulting from the same input) can be shown as one process or as a sequence of processes. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

The only way to get data into or out of a computer data storage unit is through a computer processing rectangle or offline process square. A manual process is not needed to show the sending of a document. It should be apparent from the movement of the document. Do not use manual processes to file documents. Show documents going into files. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Drawing Systems Flowcharts

SUMMARY OF SYSTEMS FLOWCHARTING
Strike a balance between clarity and clutter by using annotation judiciously and on-page connectors whenever flow lines create clutter. Avoid crossing lines whenever possible. If you must, use a “bridge.” Document only normal routines and leave exception routines for another page of the flowchart. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Documenting Enterprise Systems (SLIDE 1 OF 2)
Moving from a file-based system to an enterprise database changes the systems flowchart. The central computer would have one data store (enterprise database), not the current five computer data stores. Other changes would depend on the organization’s system implementation. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

Documenting Enterprise Systems (SLIDE 2 OF 2)

SUMMARY Common techniques used to describe and analyze business processes are documentation tools, such as: Narratives. Tables of entities and activities. DFDs. Systems flowcharts. Each technique has its own purpose, strengths, and weaknesses. © 2018 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part, except for use as permitted in a license distributed with a certain product or service or otherwise on a password-protected website for classroom use.

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