Modern Database Management
Modern Database Management
13th Edition
ISBN: 9780134792293
Author: Hoffer
Publisher: PEARSON
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Chapter 2, Problem 2.39PAE

(a)

Program Plan Intro

Drawing an ERD for the given situations and answering the given questions:

Check that the attribute name follows the naming convention or not? check if there is any associative entity in the given ERD and write it if it is present in the ERD? Check is the given ERD allow the project to be created before it is assigned to any employee? How can we change the ERD if the billing rate changes in the middles of the project?

(b)

Program Plan Intro

Draw an ERD for the data and provide definitions of all the relationship in the solution.

(c)

Program Plan Intro

Draw an ERD for the data and model the section with another methods.

(d)

Program Plan Intro

Draw an ERD for the given situation. Answer whether you draw more than one relationship between physician and patient. Provide reason for same. Mention whether you include hospital as an entity type or not and if your ERD allow for the same patient to be admitted by different physicians over time. Ways in which you include on the ERD the need to represent the date on which a patient is admitted for each time he or she is admitted.

(e)

Program Plan Intro

Draw an ERD for the given situation. Assume that credit result is not reused for multiple credit requests. Redraw the ERD for this new situation using two entity types, and then redraw it again by using one entity type. Which of these two versions do you prefer, and why?

(f)

Program Plan Intro

Draw an ERD for this situation. After that consider a new attribute, Hourly Rate, which is the rate a consultant charges a company for each hour of his or her services. Redraw the ERD to include this new attribute. Now, consider that each time a consultant works for a company, a contract is written describing the terms for this consulting engagement. Contract has attributes such as Company ID, Consultant ID, and Contract Date. Assume that a consultant can still work foronly one company at a time, redraw the ERD for this new situation. Can we move any attributes to different entity types in this latest situation? As a final situation, now consider that although a consultant can work for only one company at a time, we now need to keep the complete history of all consulting engagements for each consultant and company. Draw an ERD for this final situation. Explain why these different changes to the situation led to different data models, if they did.

(g)

Program Plan Intro

Draw an ERD for the given situation:

(h)

Program Plan Intro

Draw an ERD for the given situation:

(i)

Program Plan Intro

Draw an ERD for the given situation:

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Chapter 2 Solutions

Modern Database Management

Ch. 2 - List the four types of cardinality constraints,...Ch. 2 - Give an example, Other than those described in...Ch. 2 - What is the degree of a relationship? List the...Ch. 2 - Give an example (Other than those described in...Ch. 2 - Give an example of each of the following, other...Ch. 2 - Give an example of the use of effective (or...Ch. 2 - State a rule that says when to extract an...Ch. 2 - Prob. 2.18RQCh. 2 - In addition to explaining what action is being...Ch. 2 - For the Manages relationship in Figure 2-12a,...Ch. 2 - Explain the distinction between entity type and...Ch. 2 - Why is it recommended that every ternary...Ch. 2 - A cellular operator needs a database to keep track...Ch. 2 - Prob. 2.24PAECh. 2 - Answer the following questions concerning Figure...Ch. 2 - Prob. 2.26PAECh. 2 - You may have been assigned a CASE or a drawing...Ch. 2 - Consider the two E-R diagrams in Figure 2-25 Q,...Ch. 2 - Prob. 2.29PAECh. 2 - Are associative entities also weak entities? Why...Ch. 2 - Because Visio does not explicitly show associative...Ch. 2 - Figure 2-26 shows a grade report that is mailed to...Ch. 2 - Prob. 2.33PAECh. 2 - The Is Married To relationship in Figure 2-12a...Ch. 2 - Figure 2-27 represents a situation of students who...Ch. 2 - Figure 2-28 shows two diagrams (A and B), both of...Ch. 2 - Prob. 2.37PAECh. 2 - Review Figure 2-8LQ and Figure 2-22. Identify any...Ch. 2 - Prob. 2.39PAECh. 2 - Prob. 2.40PAECh. 2 - Prob. 2.41PAECh. 2 - Prob. 2.42PAECh. 2 - Prob. 2.43PAECh. 2 - Prob. 2.44PAECh. 2 - Prob. 2.45PAECh. 2 - Prob. 2.46PAECh. 2 - Prob. 2.47PAECh. 2 - Prob. 2.48PAECh. 2 - Draw an ERD for the following situation. (State...Ch. 2 - Prob. 2.50PAECh. 2 - Prob. 2.51PAECh. 2 - Review your answer to Problem and Exercise 2-49 if...
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