Database Application

FIND A SOLUTION AT Academic Writers Bay

Exercise 3.18: Show an alternative design for the attribute described below, that uses only entity types (including weak entity types, if needed) and relationship types.


{ PreviousEducation ( CollegeName, StartDate, EndDate,

{ Degree (DegreeName, Month, Year) },

{ Transcript (CourseName, Semester, Year, Grade) } ) }


Exercise 3.19: Consider the ER diagram in Figure 3.21, which shows a simplified schema for an airline reservations system. Extract from the ER diagram the requirements and constraints that produced this schema. Try to be as precise as possible in your requirements and constraints specification.



Exercise 5.11: Suppose that each of the following Update operations is applied directly to the database state shown in Figure 5.6. Discuss all integrity constraints violated by each operation, if any, and the different ways of enforcing these constraints.


Insert <‘Robert’, ‘F’, ‘Scott’, ‘943775543’, ‘1972-06-21’, ‘2365 Newcastle Rd, Bellaire, TX’, M, 58000, ‘888665555’, 1> into EMPLOYEE.


Insert <‘ProductA’, 4, ‘Bellaire’, 2> into PROJECT.


Insert <‘Production’, 4, ‘943775543’, ‘2007-10-01’> into DEPARTMENT.


Insert <‘677678989’, NULL, ‘40.0’> into WORKS_ON.


Insert <‘453453453’, ‘John’, ‘M’, ‘1990-12-12’, ‘spouse’> into DEPENDENT.


Delete the WORKS_ON tuples with Essn = ‘333445555’.


Delete the EMPLOYEE tuple with Ssn = ‘987654321’.


Delete the PROJECT tuple with Pname = ‘ProductX’.


Modify the Mgr_ssn and Mgr_start_date of the DEPARTMENT tuple with Dnumber = 5 to ‘123456789’ and ‘2007-10-01’, respectively.


Modify the Super_ssn attribute of the EMPLOYEE tuple with Ssn = ‘999887777’ to ‘943775543’.


Modify the Hours attribute of the WORKS_ON tuple with Essn = ‘999887777’ and Pno = 10 to ‘5.0’.



Exercise 5.13: Consider the relation CLASS(Course#, Univ_Section#, Instructor_name, Semester, Building_code, Room#, Time_period, Weekdays, Credit_hours). This represents classes taught in a university, with unique Univ_section#s. Identify what you think should be various candidate keys, and write in your own words the conditions or assumptions under which each candidate key would be valid.


Exercise 5.14: Consider the following six relations for an order-processing database application in a company:


CUSTOMER(Cust#, Cname, City)

ORDER(Order#, Odate, Cust#, Ord_amt)

ORDER_ITEM(Order#, Item#, Qty)

ITEM(Item#, Unit_price)

SHIPMENT(Order#, Warehouse#, Ship_date)

WAREHOUSE(Warehouse#, City)


Here, Ord_amt refers to total dollar amount of an order; Odate is the date the order was placed; and Ship_date is the date an order (or part of an order) is shipped from the warehouse. Assume that an order can be shipped from several warehouses. Specify the foreign keys for this schema, stating any assumptions you make. What other constraints can you think of for this database?

Welcome to one of the bestassignmenthelpcompanies  online .

·         Do you want to order for a customized assignment help task?

·          Click on the order now button 

·         Set up your topic, Fix the number of pages, Fix your Order instructions 

·         Set up your deadline, upload the necessary files required to complete the task, Complete the payment.

 We delivery high quality and non plagiarized tasks within the stipulated time given 


Order from Academic Writers Bay
Best Custom Essay Writing Services


Why Choose Us?

  • non-plagiarized Papers
  • 24/7 /365 Service Available
  • Affordable Prices
  • Any Paper, Urgency, and Subject
  • Will complete your papers in 6 hours
  • On-time Delivery
  • Money-back and Privacy guarantees
  • Unlimited Amendments upon request
  • Satisfaction guarantee

How It Works

  • Click on the “Place Your Order” tab at the top menu or “Order Now” icon at the bottom and a new page will appear with an order form to be filled.
  • Fill in your paper’s requirements in the "PAPER DETAILS" section.
  • Fill in your paper’s academic level, deadline, and the required number of pages from the drop-down menus.
  • Click “CREATE ACCOUNT ; SIGN IN” to enter your registration details and get an account with us for record-keeping and then, click on “PROCEED TO CHECKOUT” at the bottom of the page.
  • From there, the payment sections will show, follow the guided payment process and your order will be available for our writing team to work on it.


AcademicWritersBay.comnbsp;is an easy-to-use and reliable service that is ready to assist you with your papers 24/7/ 365days a year. 99% of our customers are happy with their papers. Our team is efficient and will always tackle your essay needs comprehensively assuring you of excellent results. Feel free to ask them anything concerning your essay demands or Order. is a private company that offers academic support and assistance to students at all levels. Our mission is to provide proficient andnbsp;high quality academic servicesnbsp;to our highly esteemed clients. is equipped with competent andnbsp;proficient writersnbsp;to tackle all types of your academic needs, and provide you with excellent results. Most of our writers are holders ofnbsp;master's degreesnbsp;ornbsp;PhDs, which is an surety of excellent results to our clients. We provide assistance to students all over the world.
We provide high quality term papers, research papers, essays, proposals, theses and many others. Atnbsp;, you can be sure ofnbsp;excellent gradesnbsp;in your assignments and final exams.

error: Content is protected !!