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Concept explainers
(a)
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)
Draw an ERD for the data and provide definitions of all the relationship in the solution.
(c)
Draw an ERD for the data and model the section with another methods.
(d)
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)
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)
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)
Draw an ERD for the given situation:
(h)
Draw an ERD for the given situation:
(i)
Draw an ERD for the given situation:
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Chapter 2 Solutions
EBK MODERN DATABASE MANAGEMENT,
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- 3. Problem Description: Define the Circle2D class that contains: Two double data fields named x and y that specify the center of the circle with get methods. • A data field radius with a get method. • A no-arg constructor that creates a default circle with (0, 0) for (x, y) and 1 for radius. • A constructor that creates a circle with the specified x, y, and radius. • A method getArea() that returns the area of the circle. • A method getPerimeter() that returns the perimeter of the circle. • • • A method contains(double x, double y) that returns true if the specified point (x, y) is inside this circle. See Figure (a). A method contains(Circle2D circle) that returns true if the specified circle is inside this circle. See Figure (b). A method overlaps (Circle2D circle) that returns true if the specified circle overlaps with this circle. See the figure below. р O со (a) (b) (c)< Figure (a) A point is inside the circle. (b) A circle is inside another circle. (c) A circle overlaps another…arrow_forward1. Explain in detail with examples each of the following fundamental security design principles: economy of mechanism, fail-safe default, complete mediation, open design, separation of privilege, least privilege, least common mechanism, psychological acceptability, isolation, encapsulation, modularity, layering, and least astonishment.arrow_forwardSecurity in general means the protection of an asset. In the context of computer and network security, explore and explain what assets must be protected within an online university. What the threats are to the security of these assets, and what countermeasures are available to mitigate and protect the organization from such threats. For each of the assets you identify, assign an impact level (low, moderate, or high) for the loss of confidentiality, availability, and integrity. Justify your answers.arrow_forward
- Please include comments and docs comments on the program. The two other classes are Attraction and Entertainment.arrow_forwardObject-Oriented Programming In this separate files. ent, you'll need to build and run a small Zoo in Lennoxville. All classes must be created in Animal (5) First, start by building a class that describes an Animal at a Zoo. It should have one private instance variable for the name of the animal, and one for its hunger status (fed or hungry). Add methods for setting and getting the hunger satus variable, along with a getter for the name. Consider how these should be named for code clarity. For instance, using a method called hungry () to make the animal hungry could be used as a setter for the hunger field. The same logic could be applied to when it's being fed: public void feed () { this.fed = true; Furthermore, the getter for the fed variable could be named is Fed as it is more descriptive about what it answers when compared to get Fed. Keep this technique in mind for future class designs. Zoo (10) Now we have the animals designed and ready for building a little Zoo! Build a class…arrow_forward1.[30 pts] Answer the following questions: a. [10 pts] Write a Boolean equation in sum-of-products canonical form for the truth table shown below: A B C Y 0 0 0 1 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 1 1 0 1 0 1 1 0 1 1 1 1 0 a. [10 pts] Minimize the Boolean equation you obtained in (a). b. [10 pts] Implement, using Logisim, the simplified logic circuit. Include an image of the circuit in your report. 2. [20 pts] Student A B will enjoy his picnic on sunny days that have no ants. He will also enjoy his picnic any day he sees a hummingbird, as well as on days where there are ants and ladybugs. a. Write a Boolean equation for his enjoyment (E) in terms of sun (S), ants (A), hummingbirds (H), and ladybugs (L). b. Implement in Logisim, the logic circuit of E function. Use the Circuit Analysis tool in Logisim to view the expression, include an image of the expression generated by Logisim in your report. 3.[20 pts] Find the minimum equivalent circuit for the one shown below (show your work): DAB C…arrow_forward
- Principles of Information Systems (MindTap Course...Computer ScienceISBN:9781285867168Author:Ralph Stair, George ReynoldsPublisher:Cengage LearningCOMPREHENSIVE MICROSOFT OFFICE 365 EXCEComputer ScienceISBN:9780357392676Author:FREUND, StevenPublisher:CENGAGE LNp Ms Office 365/Excel 2016 I NtermedComputer ScienceISBN:9781337508841Author:CareyPublisher:Cengage
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