Database Management Systems – Previous Year Questions
218 questions from past UGC NET Paper 2 – Computer Science papers, each with the correct answer. Open any question for its explanation.
- In concurrency control, phantom problem may occur, when-
- Match the LIST-I with LIST-II
- The degree of a relation in database is
- Match List I with List II. List I: A. Project Join Normal Form, B. The lost update problem, C. Discretionary Access Control, D. Data Manipulation Language. List II: I. Concurrency, II. Fifth Normal Form, III. SQL, IV. S…
- Consider transactions T1: r1(x); r1(z); w1(z) T2: r2(y); r2(z); w2(z) T3: r3(y); r3(x); w3(y), and schedules S1: r1(x); r3(y); r3(x); r2(y); r2(z); w3(y); w2(z); r1(z); w1(x); w1(z) and S2: r1(x); r3(y); r2(y); r3(x); r…
- Arrange the following phases of database design in the correct order : (A) Physical Design (B) Conceptual Design (C) Logical Design (D) Requirement Analysis
- Which of the following statements is/are false? A. A user can assign privileges to any user on any relation. B. A user can assign privileges to any user on its own relations only, C. System error that leads to accessibi…
- Which of the following tables is likely to have a foreign key referencing another table in the database system implemented by the company ?
- Which of the following best describes the relationship between the "orders" table and the "Customers" table in the company's database system?
- Match List - I with List - II.
- Find the number of tuples obtained by applying the right outer join X ⟖ (X.S = Y.S) Y.
- The result of the operation X ⟖ (X.S = Y.S) Y (right outer join) will be:
- Which of the following join is used to get all the tuples of relation X and Y with Null values of corresponding missing values?
- Number of tuples by applying right outer join on relation X and Y is/are :
- Let R(A, B, C, D) be a relational schema with dependencies A → B, B → C, C → D and D → B. The decomposition of R into (A, B), (B, C), (B, D):
- Which of the following scenario may lead to an irrecoverable error in a database system?
- Given the basic E R diagram and relational model, which of the the following is incorrect?
- Given below are two statements: Which of the following concurrency control protocol ensures both conflict serializability and freedom from deadlock? Statement I: Two phase locking Statement II: Timestamp ordering In the…
- Let T1 transfer ₹50 from account A to account B: 1 Read(A); 2 A := A − 50; 3 Write(A); 4 Read(B); 5 B := B + 50; 6 Write(B). What is the state of the database just after step 3 but before step 5?
- Consider the relation Student(stuid, dept, clsroll) with FDs: FD1: stuid → dept, FD2: dept → stuid, FD3: stuid → clsroll, FD4: clsroll → stuid, FD5: dept → clsroll. Which FDs can be removed to obtain a canonical cover?…
- Match List I with List II
- Consider the schedule S: t1: R2(X), R3(Y); t2: W2(X), W3(Y); t3: R1(Y), R4(X); t4: W1(Y), W4(X); t5: R3(X); t6: W3(X). Choose the correct serial execution order equivalent to S.
- Given below are the two statements: Statement I : Any retrieval request that is specified in the basic relational algebra can also be specified in relational calculus. Statement II : Any retrieval request that is specif…
- Which of the following queries would retrieve the roll number and names of students who have enrolled for all the prerequisite courses of the course number 324 ?
- Given query: select s.rollno from students where s.sex = ALL (select f.sex from professor f where f.empid = s.advisor). Consider the following statements about the given query that retrieves the set of all students whos…
- Which of the following queries would compute, for each department, the total credits of all the courses offered by the department?
- Which of the following queries would retrieve the dept id and name of all the departments that are such that the total of the credits of all the offered courses by the department is strictly greater than 40 ?
- Given query: select s.rollno, s.name from student s where EXISTS (select c.courseid from course c Where c.deptno =5 and EXISTS (select e.* from enrollment e where e.courseid = c.courseid and e.rollno = s.rollno)); Which…
- Identify the incorrect statement(s).
- Consider the two relations below. The primary keys are underlined. Identify all possible foreign key(s) from the options based only on the two Q relations. EMP (eid, ename, did) DEPT (did, dname)