417 LAB ACTIVITY 4B: Preparing a Decomposition Diagram

WHY:

This activity is designed to give you practice using Systems Architect to design and draw Decomposition Diagrams. You will use this type of diagram to model the structure of the system pertaining to your project. You will find it very helpful to draw decomposition diagrams to obtain an overview of the processes in systems you design and their relationship to the other processes in the system.

LEARNING OBJECTIVES:

1. Understand how to prepare a Decomposition Diagram.
2. Learn how to gain more control over the Decomposition Diagram facility in System Architect.
3. Discover how to subdivide a system into subsystems.

PERFORMANCE CRITERIA:

1. Quality of the answers to the Critical Thinking Questions.
   • Completeness
   • Clarity
   • Depth
2. Quality of the Decomposition Diagram.

RESOURCES:

1. System Architect Help System and Manuals;
2. Lab Activity 3; Class Activity 8;
3. Chapter 6, Systems Analysis and Design Methods
4. 40 minutes

PLAN:

1. Choose roles if you have not already done so.
   
   
2. Work through the model decomposition diagram for minicase 1 on page 257. We developed the context diagram for this problem in Activity 8.
   
   
3. Develop a decomposition diagram for the CAMPAIGN PLEDGE SYSTEM problem defined in Lab Activity 4 using System Architect's Decomposition Diagram facility.
   
   
4. Begin work on milestone 4 for your project.

MODEL:

Before preparing the decomposition diagram, we must separate the system into its primary subsystems or functions. It is clear that the TEXTBOOK INVENTORY SYSTEM can be divided into the SALES and ORDER subsystems. Under the SALES subsystem comes the filling of the BOOK REQUEST and preparing the SALES RECEIPT. Under the ORDER subsystem comes the analysis of the TEXTBOOK MASTER LIST to determine how many of each book to buy, the preparation of PURCHASE ORDERS and the updating of the inventory when a PACKING SLIP with an order is received. The following decomposition diagrams pertains:

				 ___________
				|  TEXTBOOK |
				| INVENTORY |
				|   SYSTEM  |
				 -----|-----
				      |
		______________________|____________________
		|					  |
		|					  |
	    ----------				    ------------
	   |  SALES   |				   |   ORDER    |
	   |SUBSYSTEM |				   | SUBSYSTEM  |
	   |	      |				   |		|
	    ----------				    ------------
		|					  |
		|					  |
	------------------		   -------------------------
	|		 |		   |			   |
	|		 |		   |			   |
  ----------	    ----------		 ----------	    ----------
 |  FILL    |	   | PREPARE  |		| GENERATE |	   | HANDLE   |
 |  BOOK    |	   | SALES    |		| PURCHASE |	   | RECEIPT  |
 | REQUEST  |	   | RECEIPT  |		|  ORDER   |	   | OF BOOKS |
  ----------	    ----------		 ----------	    ----------

CRITICAL THINKING QUESTIONS:

1. Which of the four lower-level activities in the decomposition diagram in the model is/are likely to be exploded further?
   
   
2. Generally, we separate the processes under each subsystem into transactions and reports. Into which of these categories do each of the four lower-level processes in the decomposition diagram in the model fall?

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