Q. Find the false statement :

View solution

Q. Consider the table:

Student (stuid, name, course, marks)
Which one of the following two queries is correct to find the highest marks student in course 5 ?

Q.1. Select S.stuid From student S Where not exists  (select * from student e where e.course = '5' and e.marks ≥s.marks)

Q.2. Select s.stuid From student S Where s.marks >any (select distinct marks from student S where s.course =5)

View solution

Q. Armstrong (1974) proposed systematic approach to derive functional dependencies. Match the following w.r.t. functional dependencies:

a.Decomposition Rule (i)   If X →Y and Z →W then {X, Z} → {Y, W}

b. Union Rule (ii)  If X →Y an  {Y,W} → Z then {X, W} → Z

c. Composition Rule (iii) If X →Y and X →Z then X → {Y, Z}
 
d. Pseudo transitivity Rule (iv) If X →{Y,Z} and  {Y,W} → Z then X → Y and  X →Z

View solution

Q. Match the following:
List - I                                         List - II

a. Secondary                          i.    Functional Dependency
Index

b. Nonprocedural                  ii.  B-Tree
Query
Language

c. Closure of                           iii. Relational Algebraic
set of                                                Operation
Attributes

d.  Natural                              iv. Domain Calculus
JOIN

View solution

Q. The best normal form of relation scheme R(A. B, C, D) along with the set of functional dependencies F = {AB → C, AB → D, C → A, D → B} is

View solution

Q. Identify the minimal key for relational scheme R(A, B, C, D, E) with functional dependencies F = {A → B, B → C, AC → D}

View solution

Q. Division operation is ideally suited to handle queries of the type :

View solution

Q. What kind of mechanism is to be taken into account for converting a weak entity set into strong entity set in entity-relationship diagram?

View solution

Q. Which of the following is true?

I.  Implementation of self-join is possible in SQL with table alias.

II. Outer-join operation is basic operation in relational algebra.

III. Natural join and outer join operations are equivalent.

View solution

Q. Which of the following is correct?

I. Two phase locking is an optimistic protocol.
II. Two phase locking is pessimistic protocol
III. Time stamping is an optimistic protocol.
IV. Time stamping is pessimistic protocol.

View solution

Q. ________________rules used to limit the volume of log information that has to be handled and processed in the event of system failure involving the loss of volatile information.

View solution

Q. Let R = ABCDE is a relational scheme with functional dependency set F = {A -> B, B ->C,AC -> D}. The attribute closures of A and E are

View solution

Q. Consider the following statements:

I. Re-construction operation used in mixed fragmentation satisfies commutative rule.
II. Re-construction operation used in vertical fragmentation satisfies commutative rule
Which of the following is correct?

View solution

Q. Which of the following is false?

View solution

Q. An Assertion is a predicate expressing a condition we wish database to always satisfy. The correct syntax for Assertion is :

View solution

Q. Which of the following concurrency protocol ensures both conflict serializability and freedom from deadlock ?

(a) 2-phase Locking
(b) Time stamp - ordering

View solution

Q. Drop Table cannot be used to drop a Table referenced by ________________ constraint.

(a) Primary key (b) Sub key (c) Super key (d) Foreign key

View solution

Q. Database applications were built directly on top of file system to overcome the following drawbacks of using file systems.
(a) Data redundancy and inconsistency
(b) Difficulty in accessing Data
(c) Data isolation
(d) Integrity problems

View solution

Q. For a weak entity set to be meaningful, it must be associated with another entity set in combination with some of their attribute values, is called as :

View solution

Q. Which of the following statements is FALSE about weak entity set ?

View solution