A directory of Objective Type Questions covering all the Computer Science subjects. Here you can access and discuss Multiple choice questions and answers for various compitative exams and interviews.

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

(a) Primary key (b) Sub key (c) Super key (d) Foreign key
a. (a)
b. (a), (b) and (c)
c. (d)
d. (a) and (d)
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Answer: (c).(d)

32. 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
a. (a)
b. (a) and (d)
c. (a), (b) and (c)
d. (a), (b), (c) and (d)
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Answer: (d).(a), (b), (c) and (d)

33. 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 :
a. Neighbour Set
b. Strong Entity Set
c. Owner entity set
d. Weak Set
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Answer: (c).Owner entity set

34. Which of the following statements is FALSE about weak entity set ?
a. Weak entities can be deleted. automatically when their strong entity is deleted
b. Weak entity set avoids the data duplication and consequent possible inconsistencies caused by duplicating.the key of the strong entity
c. A weak entity set has no primary keys unless attributes of the strong entity set on which it depends are included
d. Tuples in a weak entity set are not partitioned according to their relationship with tuples in a strong entity set
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Answer: (d).Tuples in a weak entity set are not partitioned according to their relationship with tuples in a strong entity set

35. Let E1 and E2 be two entities in E-R diagram with simple single valued attributes. R1 and R2 are two relationships between E1 and E2 where R1 is one - many and R2 is many - many. R1 and R2 do not have any attribute of their own. How many minimum number of tables are required to represent this situation in the Relational Model?
a. 4
b. 3
c. 2
d. 1
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Answer: (b).3

36. The STUDENT information in a university stored in the relation STUDENT (Name, SEX, Marks, DEPT_Name)
Consider the following SQL Query SELECT DEPT_Name from STUDENT where SEX = 'M' group by DEPT_Name having avg (Marks)>SELECT avg (Marks) from STUDENT. It returns the Name of the Department for which:
a. The Average marks of Male students is more than the average marks of students in the same Department
b. The average marks of male students is more than the average marks of students in the University
c. The average marks of male students is more than the average marks of male students in the University
d. The average marks of students is more than the average marks of male students in the University
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Answer: (b).The average marks of male students is more than the average marks of students in the University

37. Select the 'False' statement from the following statements about Normal Forms :
a. Lossless preserving decomposition into 3NF is always possible
b. Lossless preserving decomposition into BCNF is always possible
c. Any Relation with two attributes is in BCNF
d. BCNF is stronger than 3NF
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Answer: (b).Lossless preserving decomposition into BCNF is always possible

38. The Relation Vendor Order (V_no, V_ord_no, V_name, Qty_sup, unit_price) is in 2NF because:
a. Non_key attribute V_name is dependent on V_no which is part of composite key
b. Non_key attribute V_name is dependent on Qty_sup
c. Key attribute Qty_sup is dependent on primary_key unit price
d. Key attribute V_ord_no is dependent on primary_key unit price
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Answer: (a).Non_key attribute V_name is dependent on V_no which is part of composite key

39. The relation schemas R1 and R2 form a Lossless join decomposition of R if and only if :

(a)          R1⌒ R2 ⇒ (R1- R2)

(b)          R1→ R2

(c)          R1⌒ R2 ⇒ (R1- R2)

(d)         R2→ R1⌒R2
a. (a) and (b) happens
b. (a) and (d) happens
c. (a) and (c) happens
d. (b) and (c) happens
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Answer: (c).(a) and (c) happens

40. In the indexed scheme of blocks to a file, the maximum possible size of the file depends on :
a. The number of blocks used for index and the size of index
b. Size of Blocks and size of Address
c. Size of index
d. Size of Block
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Answer: (a).The number of blocks used for index and the size of index

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