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.
- Refer table, structures given above. The university decided to give all employees in the 'SCIENCE' department a 20% rise in salary. Which of the following query/queries will compute the above results? (A) UPDATE EMPLOYE…
- Which of the component module of DBMS does rearrangement and possible ordering of operations, eliminate redundancy in query and use efficient algorithms and indexes during the exceution of a query?
- Given two tables R1(x,y) and R2(y,z) with 50 and 30 numbers of tuples respectively. Find the maximum number of tuples in the output of natural join between tables R1 and R2 i.e. R1 * R2. (* - Natural Join)
- Given two tables EMPLOYEE (EID, ENAME, DEPTNO) DEPARTMENT (DEPTNO, DEPTNAME) Find the most appropriate statement of the given query : Select count (*) 'total' from EMPLOYEE where DEPTNO IN (D1, D2) group by DEPTNO havin…
- Find the minimum number of tables required for converting the following entity relationship diagram into a relational database.
- Two concurrent executing transactions 1 and T 2 are allowed to update same stock item say ' A ' in an uncontrolled manner. In such scenario, following problems may occur : (a) Dirty read problem (b) Lost update problem…
- Minimal cover of functional F dependency set is
- Identify primary key of table with F functional dependency set
- Identify the normal form in which relation R belong to
- Identify the redundant functional dependency in F
- Assume that given table R is decomposed in two tables R (A, B, C) 1 with functional dependency set f = {A → B, A → C} 1 and R (A, D, E) FD 2 with set F = {A → D, D → E} 2 . Which of the following option is true w.r.t. g…
- Which of the following has same expressive power with regard to relational query language? (a) Relational algebra and domain relational calculus (b) Relational algebra and tuples relational calculus (c) Relational algeb…
- Which of the following features is supported in the relational database model?
- With respect to relational algebra, which of the following operations are included for mathematical set theory? (a) Join (b) Intersection (c) Cartisian product (d) Project
- In relational databases, if relation is in , then which of the following is true about relation R ?
- Which of the following key constraints is required for functioning of foreign key in the context of relational databases?
- In relational database management, which of the following is/are property/properties of candidate key? P : Uniqueness Q : Irreducibility
- Which of the following statements are DML statements? (a) Update [tablename] = Set [ columnname] VALUE (b) Delete [tablename] (c) Select * from [tablename]
- Hadoop (a big data tool) works with number of related tools. Choose from the following, the common tools included into Hadoop :
- A table has attributes Employee_id (primary key) and Manager_id (foreign key referencing Employee_id with ON DELETE CASCADE), with tuples (20, 40), (25, 40), (30, 35), (35, 20), (40, 45), (45, 25). On deleting the tuple…
- An attribute A of datatype varchar(20) has the value 'xyz', and the attribute B of datatype char(20) has the value 'lmnop'. Then attribute A has ___ spaces and attribute B has ___ spaces.
- Data warehouse contains _____ data that is never found in the operational environment.
- _____command is used to remove a relation from an SQL database.
- Which of the following statements is/are true? (i) Facebook has the world's largest Hadoop cluster. (ii) Hadoop 2.0 allows live stream processing of real-time data.
- Data scrubbing is
- Consider a relation schema R = (A, B, C, D, E, F) on which the following functional dependencies hold : A → B B, C → D E → C D → A What are the candidate keys of R?
- Consider two transactions on account A (initial balance 20,000): T1 transfers 5,000 to account B, then T2 applies 10% interest to A. The log is: (i) T1 start (ii) T1, A, old = 20,000, new = 15,000 (iii) T1, B, old = 12,…
- Consider the tables Students(Roll-No, Name) and Performance(Roll-No, Course, Marks) shown below; Students also contains the row (18CS103, Ramesh). Primary keys are underlined. Consider the query: SELECT S.Name, SUM(P.Ma…
- A clustering index is defined on the fields which are of type
- In RDBMS, which type of Join returns all rows that satisfy the join condition ?