Consider the following instance of relation Sells(book_title, library, price): Sells book_title library price The grand design Noura 20,000 Brief history of time Noura 15,000 The grand design Malik's 18,000 Brief history of time Malik's 16,000 Quantum computers Malik's 25,000 Brief history of time Al Dirasat 21,000 Which ones of the following queries could be used to determine the libraries that do not sell book 'Quantum computers'? Select one: a. Select distinct library from sells si where not exists ( select from sells where library s1.library and book title Quantum computers'); All of these B. Select distinct library from sells library not in (select library from sells where book title 'Quantum computers');

Consider the following instance of relation Sells(book_title, library, price): Sells book_title library price The grand design Noura 20,000 Brief history of time Noura 15,000 The grand design Malik's 18,000 Brief history of time Malik's 16,000 Quantum computers Malik's 25,000 Brief history of time Al Dirasat 21,000 Which ones of the following queries could be used to determine the libraries that do not sell book 'Quantum computers'? Select one: a. Select distinct library from sells si where not exists ( select from sells where library s1.library and book title Quantum computers'); All of these B. Select distinct library from sells library not in (select library from sells where book title 'Quantum computers');

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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1. Consider the following relations:Student (snum: integer, sname: string, major: string, level: string, age: integer)Class (name: string, meets at: string, room: string, fid: integer)Enrolled (snum: integer, cname: string)Faculty (fid: integer, fname: string, deptid: integer)The meaning of these relations is straightforward; for example, Enrolled has onerecord per student-class pair such that the student is enrolled in the class. Level is atwo character code with 4 different values (example: Junior: A Level etc)Write the following queries in SQL. No duplicates should be printed in any of theanswers.i. Find the names of all Juniors (level = A Level) who are enrolled in a classtaught by Prof. Kwizeraii. ii. Find the names of all classes that either meet in room R128 or have five ormore Students enrolled.iii. Find the names of all students who are enrolled in two classes that meet atthe same time.
Write a relation algebra based on the following algebra: Book (BookID, Price, Year, Author, Subject) BorrowLog (BID, BookID, CustomerID, DateTime) Customer (CustomerID, CustomerName, Address, City) 1. List all tuples from books which their subjects are database 2. List all tuples from books published after 2010 which their subjects are database and the prices are at least 450 3. List information about author and subject from the relation, Book
Suppose RR is a relation with attributes A1,A2,…,AnA1,A2,…,An. How many superkeys will RR have if a) The only candidate key is A1A1. b) The only candidate keys are A1A2A1A2 and A1A3A1A3.
Consider a database that consists of the following relations.SUPpLIER(Sno. Sname)PART(Pno, Pname)PROJECT(Jno, Jname)SUPPLY(Sno, Pno, Jno)The database records information about suppliers, parts, and projectsandincludes a ternary relationship between suppliers, parts, and projects.Thisrelationship is a many-many-many relationships. Specify and execute thefollowingqueries using the relational algebraRetrieve the part numbers that are supplied to exactly two projects.b. Retrieve the names of suppliers who supply more than two parts toproject J11c. Retrieve the part numbers that are supplied by every supplier.d. Retrieve the project names that are supplied by supplier S1' only.e. Retrieve the names of suppliers who supply at least two different partseach to at least two different projects.
Consider the following relations: Employee(E_id: integer, E_name: string, Age: integer, Salary: real) Works(E_id: integer, Dep_id: integer, Start_date: date) Department(Dep_id: integer, Dep_name: string, Budget: real, Manager_E_id: integer) What referential integrity constraints exist between these relations? What are the options for enforcing these constraints when a user attempts to delete a Dept tuple?
Suppose that you are given a relation R = (A,B,C,D,E) with the following functional dependencies: {BC → ADE, D → B}. Find all candidate keys. thank you in advance
Write a relation algebra based on the following algebra: Book (BookID, Price, Year, Author, Subject) BorrowLog (BID, BookID, CustomerID, DateTime) Customer (CustomerID, CustomerName, Address, City) 1. List all of the customer names who have borrowed the book written by James Clear 2. List the subject of the books that were borrowed on the date, 2021-10-07, but not on 2021-10-01 3. List the subject of the books that were borrowed by the customers who are in Bangkok.
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 Give reasons to explain if this is in 3NF or not. If not, decompose it to 3NF.
Suppose we have three relations r(A, B), s(B, C), and t(B, D), with all attributesdeclared as not null. Give instances of relations r, s, and t such that in the result of(r natural left outer join s) natural left outer join tattribute C has a null value but attribute D has a non-null value.
Consider the following relation: r (A1, A2, A3). For all the states of the relation, the result of Query #1 is always the same as that of Query #2. Specify the primary key of the relation r (30 points); Explain why it must be the primary key.Query #1: sr1.A2=r2.A2 Ù r1.A1=r2.A1 (rr1 (r) ´ rr2 (r))Query #2: select *from r as r1, r as r2where r1.A1=r2.A1
Suppose relations R(A,B) and S(B,C,D) are as follows
1. Consider a relation schema R1(A, B, C, D) that satisfies the set of functional dependencies F1 ={A→B, B→C, C→A}.a) Calculate A + and (AC)+b) Can AB→ C? Justify your answer.c) Find all the candidate keys of R1 using F1 and show your steps to find them. 2. Consider a relation schema R2(A, B, C, D) that satisfies the set of functional dependencies F2 = {A→B, C→D, D→AC}.a) Is (AD) is candidate key of R2? Justify your answer.b) Is R2 in BCNF? Explain the reason to your answer.c) If R2 is not in BCNF, give a lossless-join BCNF decomposition of R2. Is this decomposition dependency preserving? 3. Consider a relation schema R3(A, B, C, D, E) that satisfies the set of functional dependencies F3 = {A → BC, AC → BD}.a) Calculate (AC)+ and (AE)+b) Is AB → C in F3 +? Justify your answer.c) Find the canonical cover Fc of F3.d) Is R3 in 3NF? Explain the reason to your answer. If R3 is not in 3NF, give a lossless-join, dependency preserving 3NF decomposition of R3.