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ABOUT ME a FOLLOW M COMPUTER ENGINEER https://unacademy.com/user/hellosonu01 EDUCATOR@ UNACADEMY CONTENT WRITER DOUBT RESOLVER HOME TUTOR QUORA WRITER GOOD ADVISOR Sweta Kumari Software Engineer Pursuing M.TECH (CSE) ISelected in 2 IT MNC(Java) Research Paper (NCCCS) IQuora Writer 12+ yr Teaching Exp. IYoutuber D 11,614 Views in last 30 days 50,304 Lifetime Views 82 Courses 3.8k Followers183 Following
TARGET GATE CSE 2019 ur academy 2 DATABASE MANAGEMENT SYSTEM GATE PREVIOUS YEAR QUESTIONS DBMS SECTION
https/unacademy.com/user/hellosonuot .. unacademy Home Explore Plus 0 minutes today Search Courses, Topics&Educators 1,015-Credit Sweta Kumari Edit Profile Software Engineer Pursuing M.TECH (CSE) Selected in 2 IT MNC(Java) Research Paper (NCCCS) Quora Writer 12+ yr Teaching Exp. IYoutuber 11,614 Views in last 30 days 50,304 Lifetime Views 82 Courses 3.8k Followers183 Following COMPLETE SYLLABU GATE (CS/IT) - DBMS Learn WEB SERVICES SOFTWARE ENGINEERING In 60 Mautes t. By Sweta Kumari y Sweta Kumari ay Sweta Kumari (Hindi) SQL Joins With Tabular Examples-GATE (CS/IT) (Hindi) Complete Software Engineering in 60 Minutes (Hindi) Web Services Tutorial For Beginners in 60 Minutes
KEYS IN RELATIONAL MODEL CANDIDATE KEY SUPER KEY PRIMARY KEY ALTERNATE KEY FOREIGN KEY
CONSIDER TWO TABLES: STUDENT STUD PHONE 9898765432 9976534590 8976054367 STUD STATE MUMBAI DELHI KOLKATA CHENNAI STUD NO STUD NAME SWETA SWETA RIYA PRACHI STUD COUNTRYSTUD AGE 18 20 19 1 INDIA INDIA INDIA 4 STUDENT COURSE COURSE NO C1 C2 C2 STUD NO COURSE NAME DATABASE COMPUTER COMPUTER
GATE CS 2014 Given the following statements: Which one of the following statements is CORRECT? S1: A foreign key declaration can always (A) S1 is TRUE and S2 is FALSE. artion in SQL. (B) Both S1 and S2 are TRUE. together form the primary key, the (C) S1 is FALSE and S2 is TRUE. CREATE TABLE S ( a INTEGER, d INTEGER, e (D) Both S1 and S2 are FALSE. (a) references R) be replaced by an equivalent check S2: Given the table R(a,b,c) where a and b following is a valid table definition. INTEGER, PRIMARY KEY (d), FOREIGN KEY
Consider the relation account (customer, balance) where customer is a primary key and there are no null values. We would like to rank customers according to decreasing balance. The customer with the largest balance gets rank 1. ties are not broke but ranks are skipped: if exactly two customers have the largest balance they each get rank 1 and rank 2 is not assigned GATE CS 2006 1. Query1 will produce the same row set as Query2 for some Query1: but not all databases 2. Both Query1 and Query2 are correct implementation of the specification 3. Query1 is a correct implementation of the specification but Query2 is not 4. Neither Query1 nor Query2 is a correct implementation of the specification 5. Assigning rank with a pure relational query takes less time group by A.customer than scanning in decreasing balance order assigning ranks using ODBO select A.customer, count(B.customer) from account A, account B where A.balance <B.balance group by A.customer Query2: select A.customer, 1+count(B.customer) from account A, account B where A.balance< B.balance t implementation of Which two of the above statements are correct?
Consider the relation "enrolled(student, course)" in which (student, course) is the primary key, and the relation "paid(student, amount)" where student is the primary key. Assume no null values and no foreign keys or integrity constraints. Given the following four queries: GATE CS 2006 Query1: select student from enrolled where student in (select student from paid) Query2: select student from paid where student in (select student from enrolled) Query3: select E.student from enrolled E, paid P (A) All queries return identical row sets for any database (B) Query2 and Query4 return identical row sets for all databases but there exist databases for which Query1 and Query2 return different row sets. (C) There exist databases for which Query3 returns strictlywhere E.student P.student fewer rows than Query2 (D) There exist databases for which Query4 will encounter an integrity violation at runtime Query4: select student from paid where exists (select * from enrolled where enrolled.student- paid.student) Which two of the above statements are correct?
Consider the following relational schema: employee(empld, empName, empDept) customer(custld, custName, salesRepld, rating) GATE CS 2014 a fo s with at least one of salesRepld is a foreign key referring to empld of the employee relation. Assume (A) Names of all the employees with at least one of their customers having a 'GOOD' rating. (B) Names of all the employees with at most one of their customers having a 'GOOD' rating. (C) Names of all the employees with none of their customers having a 'GOOD' rating. (D) Names of all the employees with all their customers having a 'GOOD' rating. that each employee makes a sale to at least one customer. What does the following query return? SELECT empName FROM employee E WHERE NOT EXISTS (SELECT custld FROM customer C WHERE C.salesRepld E.empld AND C.rating<>GOOD);
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