Chapter 7: Problems/Exercises
5. Consider the E-R diagram in Figure 7-20. Based on this E-R diagram, answer the following questions: a. How many EMPLOYEES can work on a project?
According to the diagram, it seems that any amount of employees can work on a project. b. What is the degree of the Used_on relationship?
The degree of the Used_on relationship is Binary (two degrees for the relationship). c. Do any associative entities appear in this diagram? If so, name them. Task is an associative entity that appears in the diagram.
d. How else could the attribute Skill be modeled?
The attribute Skill could be shown coming off of Task as another blue square attached back to Task. e. What attributes might be attached to the Works_on relationship? Different positions on the project can be attached to the Work_on relationship, like Jobs and Requirements. f. Could TOOL be modeled as an associative entity? Why or why not? Tool cannot be modeled as an associative entity because different Tools can be used on different Tasks. Sometimes you would need more or less Tools depending on what you are trying to do.
16. The owner of two pizza parlors located in adjacent towns wants to computerize and integrate sales transactions and inventory management within and between both stores. The point-of-sale component must be easy to use and flexible enough to accommodate a variety of pricing strategies and coupons. The inventory management, which will be linked to the point-of-sale component, must also be easy to use and fast. The systems at each store need to be linked so that sales and inventory levels can be determined instantly for each store and for both stores combined. The owner can allocate $40,000 for hardware and $20,000 for software and must have the new system operational in three months. Training must be short and easy. Briefly describe three alternative systems for this situation and explain how each would meet the requirements and...
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