QUESTION 2 Consider the database schema below: Company (CompnayID: integer, CompnayName: String (unique), address) Department (DepartmentID: Integer, DepartmentName: String, CompanyID: Integer) Employee (ID:integer; name:String, DepartmentID:intger (not null)) How many candidate key(s) in the Employee relation?

QUESTION 2 Consider the database schema below: Company (CompnayID: integer, CompnayName: String (unique), address) Department (DepartmentID: Integer, DepartmentName: String, CompanyID: Integer) Employee (ID:integer; name:String, DepartmentID:intger (not null)) How many candidate key(s) in the Employee relation?

Database Systems: Design, Implementation, & Management

11th Edition

ISBN:9781285196145

Author:Steven, Steven Morris, Carlos Coronel, Carlos, Coronel, Carlos; Morris, Carlos Coronel and Steven Morris, Carlos Coronel; Steven Morris, Steven Morris; Carlos Coronel

Publisher:Steven, Steven Morris, Carlos Coronel, Carlos, Coronel, Carlos; Morris, Carlos Coronel and Steven Morris, Carlos Coronel; Steven Morris, Steven Morris; Carlos Coronel

Chapter10: Transaction Management And Concurrency Control

Section: Chapter Questions

Problem 1P

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QUESTION 2 Consider the database schema below for hotels in countries. A country have many hotels, and the same hotel chain (name) are available in different countries. Country (ID: integer, Name: String (unique)) Hotel (CountryID: Integer, HotelName: String, ManagerID: Integer) How many candidate Key(s) in the hotel relation?
QUESTION 14 Consider the database schema below for cities in countries. A country have many cities, and the same city name can be found in different countries. Country (ID: integer, Name: String (unique), SN: serialNumber (int)(unique)) City (serialNo: integer (unique, not null), CountryID: Integer, CityName: String, Population: integer) The same country (ID , name) can be added twice in Country relation with different SN? No, violates entity Integrity constraint No, violates referential integrity constraint. No, violates key constraint. Yes. No, violates domain constraints.
Database Systems Question 6. Consider the following relation: Invoice(Order_ID, Order_Date, Customer_ID, Customer_Name,Customer_Address,Product_ID, Product_Desc, Price, Order_Quantity) FD1 - Order_ID -> Order_Date, Customer_ID, Customer_Name, Customer_Address FD2 - Customer_ID -> Customer_Name, Customer_Address FD3 - Product_ID -> Product_Description, Price FD4 - Order_ID, Product_ID -> Order_Quantity What are the candidate keys of this relation? Give reasons to explain if this is in 1NF or not. If not, decompose it to 1NF. Give reasons to explain if this is in 2NF or not. If not, decompose it to 2NF. Give reasons to explain if this is in 3NF or not. If not, decompose it to 3NF.
QUESTION 5 Consider the database schema below: Company (ID: integer, Name: String (unique), Address) Department (No: integer (not null), CompanyID: Integer, DepartmentName: String) Is it valid for Department to have unknown No?   No, violates key constraint.   No, violates referential integrity constraint.   Yes.   No, violates entity Integrity constraint   No, violates domain constraints.
Emp (Eno, Ename, Title, City) Project(Pno, Pname, Budget, City) Works(Eno, Pno, Resp,  Dur) SELECT         Ename, Pname FROM            Emp e, Works w, Project p WHERE         e.Eno = w.Eno AND              e.city = p.Eno AND              p.city = Newark AND              w.Dur > 40 Given the database schema and the query above and knowing that only 1% of the employees work on a project for 40 months or more, propose an optimized query plan and discuss the indexes needed
QUESTION 4 Consider the database schema below: Company (CompnayID: integer, CompnayName: String (unique), address) Department (DepartmentID: Integer, DepartmentName: String, CompanyID: Integer) Employee (ID:integer; name:String, DepartmentID:intger (not null)) Is it valid in the department relation, that two different departments to have the same value of CompanyID?   No, violates domain constraints.   No, violates key constraint.   Yes.   No, violates referential integrity constraint.   No, violates entity Integrity constraint.
QUESTION 6 Consider the database schema below: Company (CompnayID: integer, CompnayName: String (unique), address) Department (DepartmentID: Integer, DepartmentName: String, CompanyID: Integer) Employee (ID:integer; name:String, DepartmentID:intger (not null)) Is it valid in the employee relation to have the same value of DepartmentID for three different Employees?   No, violates Entity Integrity constraint   No, violates referential integrity constraint.   No, violates Key constraint.   Yes.   No, violated Domain Constraints
QUESTION 3 Consider the database schema below: Company (CompnayID: integer, CompnayName: String (unique), address) Department (DepartmentID: Integer, DepartmentName: String, CompanyID: Integer) Employee (ID:integer; name:String, DepartmentID:intger (not null)) Is it valid for an employee to work in two different departments?   No, violates entity Integrity constraint   No, violates key constraint.   Yes.   No, violates domain constraints.   No, violates referential integrity constraint.
QUESTION 7 Consider the database schema below: Company (ID: integer, Name: String (unique), Address) Department (No: integer, CompanyID: Integer, DepartmentName: String) Is it valid to have the same Company name to be repeated with two different IDs in Company relation?   Yes.   No, violates key constraint.   No, violates entity Integrity constraint   No, violates referential integrity constraint.   No, violates domain constraints.
Specify the following queries on the COMPANY relational database schema shown in Figure 3.5, using the relational operators discussed in this chapter. Also show the result of each query as it would apply to the database state of Figure 3.6. - List the managers who are controlling more than 2 projects. - List the names of employees all of whose dependents were born before 1990. - Retrieve the average salary of employees who work totally no less than 30 hours on projects.
Subject: Database Management System Consider the following relations: PERSON(P_id,_F_name, L_name,Occupation, Salary, City) ORDER(O_id, P_id, Item, Quantity, Price, Order_date) The Primary Keys are P_id and O_id respectively. Express the following queries in SQL and Relational Algebra. a) Find the person's name and city whose name starts with S. b) Find the person with the highest salary. c) Find the average salary for each Occupation. d) Find the detail of the person who has ordered any item. e) Find the name of the person who has ordered in the same date. f) Find the game of the person who hasn't ordered any item. g) Find the highest ordered item. h) Find the detail of Item with lowest Price.
QUESTION 17 Consider the database schema below for cities in countries. A country have many cities, and the same city name can be found in different countries. Country (ID: integer, Name: String (unique)) City (serialNo: integer (unique, not null), CountryID: Integer, CityName: String, Population: integer) The same country name can be repeated with two different IDs in Country relation? No, violates key constraint. No, violates entity Integrity constraint No, violates domain constraints. No, violates referential integrity constraint. Yes.

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