ATG 383 - Summer 2001 - Study Guide - Chapter 3

This page describes assignments the systems documentation assignments for May 30 and 31.

Read Chapter 3 in the Romney text, pages 56 - 71. Also, read problem 3.1, which we will cover in class. In this chapter, we are only interested in data flow diagrams and document flow charts.

Data Flow Diagrams

A data flow diagram (DFD) shows the flow of data through a system, the processes used to transform the data, and the files needed to complete processing. Additionally, it shows the sources (creators) and destinations (users) of the data. A data flow diagram, however, does not show the specific means to accomplish the work (e.g., manual process or computer process) or the format of the data (e.g., paper or electronic).

The most critical prerequisite for drawing DFDs is to understand the operation of the system you are drawing. You cannot document the way something works if you do not understand it.

Read the following and answer the questions shown below:

CPAs send research requests to the AICPA library and receive back bibliographies related to their questions. When the request is received, the chief librarian checks the membership 
data base (since searches are only done for members.) She also reviews the requests to determine that it is appropriate. Rejected requests are returned to the sender. 

Approved requests are forwarded to a research librarian. He searches the periodical index and prepares the bibliography. This is sent to the CPA. 

 

__________ sends input to the library system.  __________ is the DFD symbol used to show anyone / anything that sends data to the system.

 

__________ receives output from the system. __________ is the DFD symbol used to show anyone / anything that receives data from the system.

 

__________ is the type of information input into the library system. _________ and _________ are the types of information output from the library system. 

 

__________ is the DFD symbol used to show the flow of information into or out of the system.

 

__________ and __________ are the names of the two files used in the library system. __________ is the DFD symbol used to show data files within the system.

 

__________ is the number of major processing steps needed by the library system to complete its work. 

 

__________ is the symbol that will be used to show these processing steps in the DFD.

 

________________________ is the name of a special DFD that only shows the system's inputs and outputs.

 

In class, we will work on how to draw the context diagram and level 0 diagram for this system.

Read very carefully and then re-read Table 3.1 (p. 65). We will re-draw the corresponding DFD in class. Finally, for good measure, read it again. Your comprehension of what is pictured in the DFD is directly proportional to your understanding of the system being drawn.

Flowcharts

Flowcharts show how the work is actually done. To accomplish this, a larger group of symbols is needed. Review the following in Table 3.8. I will go over their usage in class:

Input / Output Symbols

Processing Symbols

Storage Symbols

Flow and Miscellaneous Symbols

In class, we will use these symbols to draw a flowchart for the library system discussed above. We will also draw the flowcharts related to Problem 3.1 and the payroll system in Table 3.1.

Homework due on Thursday, May 31

Draw a context diagram and level 0 DFD for the system described in Problem 3.8. Draw the level 0 DFD for the system described in Case 3.2.

For problem 3.6, I will give you a partially completed flowchart. You need to finish this flowchart. Also, draw a flowchart for Problem 3.2 (a) and (b).

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