Q.1 When R∩S = ะค , then the cost of computing R|><|S is
(A) the same as R × S
(B) greater the R × S
(C) less than R × S
(D) cannot say anything
Ans: (A)
Q.2 In SQL the word ‘natural’ can be used with
(A) inner join
(B) full outer join
(C) right outer join
(D) all of the above
Ans: (A)
Q.3 The default level of consistency in SQL is
(A) repeatable read
(B) read committed
(C) read uncommitted
(D) serializable
Ans: (D)
Q.4 If a transaction T has obtained an exclusive lock on
item Q, then T can
(A) read Q
(B) write Q
(C) both read and write Q
(D) write Q but not read Q
Ans: (C)
Q.5 Shadow paging has
(A) no redo
(B) no undo
(C) redo but no undo
(D) neither redo nor undo
Ans: (A)
Q.6 If the closure of an attribute set is the entire
relation then the attribute set is a
(A) superkey
(B) candidate key
(C) primary key
(D) not a key
Ans: (A)
Q.7 DROP is a ______________ statement in SQL.
(A) Query
(B) Embedded SQL
(C) DDL
(D) DCL
Ans: (C)
Q.8 If two relations R and S are joined, then the non
matching tuples of both R and S are ignored in
(A) left outer join
(B) right outer join
(C) full outer join
(D) inner join
Ans: (D)
Q.9 The keyword to eliminate duplicate rows from the query
result in SQL is
(A) DISTINCT
(B) NO DUPLICATE
(C) UNIQUE
(D) None of the above
Ans: (C)
Q.10 In 2NF
(A) No functional dependencies (FDs) exist.
(B) No multivalued dependencies (MVDs) exist.
(C) No partial FDs exist.
(D) No partial MVDs exist.
Ans: (C)
Q.11 Which one is correct statement?
Logical data independence provides following without
changing application programs:
(i) Changes in access methods.
(ii) Adding new entities in database
(iii) Splitting an existing record into two or more records
(iv) Changing storage medium
(A) (i) and (ii) (B) (iv) only, (C) (i) and (iv) (D) (ii)
and (iii)
Ans: (D)
Q.12 In an E-R, Y is the dominant entity and X is a
subordinate entity. Then which of the following is incorrect :
(A) Operationally, if Y is deleted, so is X
(B) existence is dependent on Y.
(C) Operationally, if X is deleted, so is Y.
(D) Operationally, if X is deleted, & remains the same.
Ans: (C)
Q.13 Relational Algebra is
(A) Data Definition Language .
(B) Meta Language
(C) Procedural query Language
(D) None of the above
Ans: (C)
Q.14 Which of the following aggregate functions does not
ignore nulls in its results?.
(A) COUNT .
(B) COUNT (*)
(C) MAX
(D) MIN
Ans: (B)
Q.15 R (A,B,C,D) is a relation. Which of the following does
not have a lossless join dependency preserving BCNF decomposition
(A) A->B, B->CD
(B) A->B, B->C, C->D .
(C) AB->C, C->AD
(D) A->BCD
Ans: (D)
Q.16 Consider the join of relation R with a relation S. If R
has m tuples and S has n tuples, then the maximum and minimum size of the join
respectively are
(A) m+n and 0
(B) m+n and |m-n|
(C) mn and 0
(D) mn and m+n
Ans: (C)
Q.17 Maximum height of a B+ tree of order m with n key
values is
(A) Logm(n)
(B) (m+n)/2
(C) Logm/2(m+n)
(D) None of these
Ans: (D)
Q.18 Which one is true statement :
(A) With finer degree of granularity of locking a high
degree of concurrency is possible.
(B) Locking prevents non – serializable schedules.
(C) Locking cannot take place at field level.
(D) An exclusive lock on data item X is granted even if a
shared lock is already held on X.
Ans: (A)
Q.19 Which of the following statement on the view concept in
SQL is invalid?
(A) All views are not updateable
(B) The views may be referenced in an SQL statement whenever
tables are referenced.
(C) The views are instantiated at the time they are
referenced and not when they are defined.
(D) The definition of a view should not have GROUP BY clause
in it.
Ans: (D)
Q.20 Which of the following concurrency control schemes is
not based on the serializability property?
(A) Two – phase locking
(B) Graph-based locking
(C) Time-stamp based locking
(D) None of these
Ans: (D)
Q.21 Which of the following is a reason to model data?
(A) Understand each user’s perspective of data
(B) Understand the data itself irrespective of the physical
representation
(C) Understand the use of data across application areas
(D) All of the above
Ans: (D)
Q.22 If an entity can belong to only one lower level entity
then the constraint is
(A) disjoint
(B) partial
(C) overlapping
(D) single
Ans: (B)
Q.23 The common column is eliminated in
(A) theta join
(B) outer join
(C) natural join
(D) composed join
Ans: (C )
Q.24 In SQL, testing whether a subquery is empty is done
using
(A) DISTINCT
(B) UNIQUE
(C) NULL
(D) EXISTS
Ans: (D)
Q.25 Use of UNIQUE while defining an attribute of a table in
SQL means that the attribute
values are
(A) distinct values
(B) cannot have NULL
(C) both (A) & (B)
(D) same as primary key
Ans: (C)
