Database Processing: Fundamentals, Design, and Implementation 13th Edition by David Kroenke, David Auer

Exercise 11

C.10. Answer Project Question 5.59, but use IDEF1X instead of the crow's foot model. Redraw Figure 5-57 in IDEF1X notation.
Figure 5-57 is shown redrawn in the question below.
PQ- 5.59. Figure 5-56 shows the specifications for single-stage air compressor products. Note that there are two product categories that are based on Air Performance: The A models are at 125 pounds per square inch of pressure, and the E models are at 150 pounds per square inch of pressure. Using the structure and example data items in this list, do the following:


A. Create a set of exclusive subtypes to represent these compressors. The supertype will have attributes for all single-stage compressors, and the subtypes will have attributes for products having the two different types of Air Performance. Assume that there might be additional products with different types of Air Performance. Specify the entities, identifiers, attributes, relationships, type of category cluster, and possible determinant.
B. Figure 5-57 shows a different model for the compressor data. Explain the entities, their type, the relationship, its type, and its cardinality. How well do you think this model fits the data shown in Figure 5-56?
C. Compare your answer in question A with the model in Figure 5-57. What are the essential differences between the two models? Which do you think is better?
D. Suppose you had the job of explaining the differences in these two models to a highly motivated, intelligent end user. How would you accomplish this?