Database Management System-1

Multiple Choice Questions (MCQs)

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1   SET concept is used in:
    (A)   Network Model
    (B)   Hierarchical Model
    (C)   Relational Model
    (D)   None of these

2   Relational Algebra is
    (A)   Data Definition Language
    (B)   Meta Language
    (C)   Procedural Query Language
    (D)   None of the above

3   Key to represent the relationship between tables is called
    (A)   Primary key
    (B)   Secondary Key
    (C)   Foreign Key
    (D)   None of these

4   —– produces the relation that has attributes of R1 and R2
    (A)   Cartesian product
    (B)   Difference
    (C)   Intersection
    (D)   Product

5   The file organization that provides very fast access to any arbitrary record of a file is
    (A)   Ordered file
    (B)   Unordered file
    (C)   Hashed file
    (D)   B—tree

6   DBMS helps achieve
    (A)   Data independence
    (B)   Centralized control of data
    (C)   Neither A or B
    (D)   Both A and B

7   Which of the following are the properties of entities?
    (A)   Groups
    (B)   Table
    (C)   Attributes
    (D)   Switchboards

8   In a relation
    (A)   Ordering of rows is immaterial
    (B)   No two rows are identical
    (C)   A and B both are true
    (D)   None of these

9   Which of the following is correct?
    (A)   A SQL query automatically eliminates duplicates
    (B)   SQL permits attribute names to be repeated in the same relation
    (C)   A SQL query will not work if there are no indexes on the relation
    (D)   None of these

10   It is better to use files than a DBMS when there are
    (A)   Stringent real-time requirements
    (B)   Multiple users wish to access the data
    (C)   Complex relationships among data
    (D)   All of the above

11   The conceptual model is
    (A)   Dependent on hardware
    (B)   Dependent on software
    (C)   Dependent on both hardware and software
    (D)   Independent of both hardware and software

12   What is a relationship called when it is maintained between two entities?
    (A)   Unary
    (B)   Binary
    (C)   Ternary
    (D)   Quaternary

13   Which of the following operation is used if we are interested in only certain columns of a table?
    (C)   UNION
    (D)   JOIN

14   Which of the following is a valid SQL type?
    (B)   NUMERIC
    (C)   FLOAT
    (D)   All of the above

15   The RDBMS terminology for a row is
    (A)   Tuple
    (B)   Relation
    (C)   Attribute
    (D)   Degree

16   Which of the following operations need the participating relations to be union compatible?
    (A)   UNION
    (D)   All of the above

17   The full form of DDL is
    (A)   A Dynamic Data Language
    (B)   Detailed Data Language
    (C)   Data Definition Language
    (D)   Data Derivation Language

18   Which of the following is an advantage of view?
    (A)   Data security
    (B)   Derived columns
    (C)   Hiding of complex queries
    (D)   All of the above

19   Which of the following is a legal expression in SQL?
    (D)   None of the above

20   Which of the following relational algebra operations do not require the participating tables to be union-compatible?
    (A)   Union
    (B)   Intersection
    (C)   Difference
    (D)   Join

21   Which of the following is not a property of transactions?
    (A)   Atomicity
    (B)   Concurrency
    (C)   Isolation
    (D)   Durability

22   Relational Algebra does not have
    (A)   Selection operator
    (B)   Projection operator
    (C)   Aggregation operators
    (D)   Division operator

23   Checkpoints are a part of
    (A)   Recovery measures
    (B)   Security measures
    (C)   Concurrency measures
    (D)   Authorization measures

24   Tree structures are used to store data in
    (A)   Network model
    (B)   Relational model
    (C)   Hierarchical model
    (D)   File based system

25   The language that requires a user to specify the data to be retrieved without specifying exactly how to get it is
    (A)   Procedural DML
    (B)   Non-Procedural DML
    (C)   Procedural DDL
    (D)   Non-Procedural DDL

26   Precedence graphs help to find a
    (A)   Serializable schedule
    (B)   Recoverable schedule
    (C)   Deadlock free schedule
    (D)   Cascadeless schedule

27   The rule that a value of a foreign key must appear as a value of some specific table is called a
    (A)   Referential constraint
    (B)   Index
    (C)   Integrity constraint
    (D)   Functional dependency

28   The clause in SQL that specifies that the query result should be sorted in ascending or descending order based on the values of one or more columns is
    (A)   View
    (B)   Order by
    (C)   Group by
    (D)   Having

29   What is a disjoint less constraint?
    (A)   It requires that an entity belongs to no more than one level entity set
    (B)   The same entity may belong to more than one level
    (C)   The database must contain an unmatched foreign key value
    (D)   An entity can be joined with another entity in the same level entity set

30   According to the levels of abstraction, the schema at the intermediate level is called
    (A)   Logical schema
    (B)   Physical schema
    (C)   Super schema
    (D)   None of the above

31   It is an abstraction through which relationships are treated as higher level entities
    (A)   Generalization
    (B)   Specialization
    (C)   Aggregation
    (D)   Inheritance

32   A relation is in ____________ if an attribute of a composite key is dependent on an attribute of other composite key
    (A)   2NF
    (B)   3NF
    (C)   BCNF
    (D)   1NF

33   What is data integrity?
    (A)   It is the data contained in database that is non redundant
    (B)   It is the data contained in database that is accurate and consistent
    (C)   It is the data contained in database that is secured
    (D)   It is the data contained in database that is shared

34   What are the desirable properties of decomposition?
    (A)   Partition constraint
    (B)   Dependency preservation
    (C)   Redundancy
    (D)   Security

35   In an E-R diagram double lines indicate
    (A)   Total participation
    (B)   Multiple participation
    (C)   Cardinality N
    (D)   None of the above

36   The operation which is not considered a basic operation of relational algebra is
    (A)   Join
    (B)   Selection
    (C)   Union
    (D)   Cross product

37   Fifth Normal form is concerned with
    (A)   Functional dependency
    (B)   Multivalued dependency
    (C)   Join dependency
    (D)   Domain-key

38   Block-interleaved distributed parity is RAID level
    (A)   2
    (B)   3
    (C)   4
    (D)   5

39   Immediate database modification technique uses
    (A)   Both undo and redo
    (B)   Undo but no redo
    (C)   Redo but no undo
    (D)   Neither undo nor redo

40   In SQL the statement select * from R, S is equivalent to
    (A)   Select * from R natural join S
    (B)   Select * from R cross join S
    (C)   Select * from R union join S
    (D)   Select * from R inner join S

41   Which of the following is not a consequence of concurrent operations?
    (A)   Lost update problem
    (B)   Update anomaly
    (C)   Unrepeatable read
    (D)   Dirty read

42   As per equivalence rules for query transformation, selection operation distributes over
    (A)   Union
    (B)   Intersection
    (C)   Set difference
    (D)   All of the above

43   The metadata is created by the
    (A)   DML compiler
    (B)   DML pre-processor
    (C)   DDL interpreter
    (D)   Query interpreter

44   When an E-R diagram is mapped to tables, the representation is redundant for
    (A)   Weak entity sets
    (B)   Weak relationship sets
    (C)   Strong entity sets
    (D)   Strong relationship sets

45   When R∩S = f, 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

46   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

47   The default level of consistency in SQL is
    (A)   Repeatable read
    (B)   Read committed
    (C)   Read uncommitted
    (D)   Serializable

48   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

49   Shadow paging has
    (A)   No redo
    (B)   No undo
    (C)   Redo but no undo
    (D)   Neither redo nor undo

50   If the closure of an attribute set is the entire relation then the attribute set is a
    (A)   Super key
    (B)   Candidate key
    (C)   Primary key
    (D)   Not a key

51   DROP is a ______________ statement in SQL
    (A)   Query
    (B)   Embedded SQL
    (C)   DDL
    (D)   DCL

52   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

53   The keyword to eliminate duplicate rows from the query result in SQL is
    (A)   DISTINCT
    (C)   UNIQUE
    (D)   None of the above

54   In 2NF
    (A)   No functional dependencies (FDs) exist
    (B)   No multivalued dependencies (MVDs) exist
    (C)   No partial FDs exist
    (D)   No partial MVDs exist

55   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

56   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

57   Which of the following aggregate functions does not ignore nulls in its results?
    (A)   COUNT
    (B)   COUNT (*)
    (C)   MAX
    (D)   MIN

58   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

59   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

60   Maximum height of a B+ tree of order m with n key values is
    (A)   Logm(n)
    (B)   (m+n)/2
    (C)   Logm/2m+n
    (D)   None of these

61   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

62   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

63   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

64   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

65   If an entity can belong to only one lower level entity then the constraint is
    (A)   Disjoint
    (B)   Partial
    (C)   Overlapping
    (D)   Single

66   The common column is eliminated in
    (A)   Theta join
    (B)   Outer join
    (C)   Natural join
    (D)   Composed join

67   In SQL, testing whether a subquery is empty is done using
    (A)   DISTINCT
    (B)   UNIQUE
    (C)   NULL
    (D)   EXISTS

68   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

69   The cost of reading and writing temporary files while evaluating a query can be reduced by
    (A)   Building indices
    (B)   Pipelining
    (C)   Join ordering
    (D)   None of the above

70   A transaction is in __________ state after the final statement has been executed
    (A)   Partially committed
    (B)   Active
    (C)   Committed
    (D)   None of the above

71   In multiple granularity of locks SIX lock is compatible with
    (A)   IX
    (B)   IS
    (C)   S
    (D)   SIX

72   The statement that is executed automatically by the system as a side effect of the modification of the database is
    (A)   Backup
    (B)   Assertion
    (C)   Recovery
    (D)   Trigger

73   The normal form that is not necessarily dependency preserving is
    (A)   2NF
    (B)   3NF
    (C)   BCNF
    (D)   4NF

74   The normalization was first proposed by ______________
    (A)   Code
    (B)   Codd
    (C)   Boyce Codd
    (D)   Boyce

75   The division operator divides a dividend A of degree m+n by a divisor relation B of degree n and produces a result of degree
    (A)   m – 1
    (B)   m + 1
    (C)   m * m
    (D)   m

76   Which of the following is not a characteristic of a relational database model?
    (A)   Table
    (B)   Tree like structure
    (C)   Complex logical relationship
    (D)   Records

77   Assume transaction A holds a shared lock R. If transaction B also requests for a shared lock on R
    (A)   It will result in a deadlock situation
    (B)   It will immediately be rejected
    (C)   It will immediately be granted
    (D)   It will be granted as soon as it is released by A

78   In E-R Diagram total participation is represented by
    (A)   Double lines
    (B)   Dashed lines
    (C)   Single line
    (D)   Triangle

79   The FD A -> B, DB -> C implies
    (A)   DA -> C
    (B)   A -> C
    (C)   B -> A
    (D)   DB -> A

80   The graphical representation of a query is ________
    (A)   B-Tree
    (B)   Graph
    (C)   Query Tree
    (D)   Directed graph

81   Union operator is a:
    (A)   Unary Operator
    (B)   Ternary Operator
    (C)   Binary Operator
    (D)   Not an operator

82   Relations produced from an E-R model will always be
    (A)   First normal form
    (B)   Second normal form
    (C)   Third normal form
    (D)   Fourth normal form

83   Manager salary details are hidden from the employee .This is
    (A)   Conceptual level data hiding
    (B)   External level data hiding
    (C)   Physical level data hiding
    (D)   None of these

84   Which of the following is true for network structure?
    (A)   It is a physical representation of the data
    (B)   It allows many to many relationship
    (C)   It is conceptually simple
    (D)   It will be the dominant database of the future

85   Which two files are used during operation of the DBMS?
    (A)   Query languages and utilities
    (B)   DML and query language
    (C)   Data dictionary and transaction log
    (D)   Data dictionary and query language

86   A list consists of last names, first names, addresses and pin codes. If all people in the list have the same last name and same pin code a useful key would be
    (A)   The pin code
    (B)   The last name
    (C)   The compound key first name and last name
    (D)   Tr from next page

87   In b-tree the number of keys in each node is ____ than the number of its children
    (A)   One less
    (B)   Same
    (C)   One more
    (D)   Half

88   The drawback of shadow paging technique is
    (A)   Commit overhead
    (B)   Data fragmentation
    (C)   Garbage collection
    (D)   All of these

89   Which normal form is considered adequate for normal relational database design?
    (A)   2NF
    (B)   5NF
    (C)   4NF
    (D)   3NF

90   Which of the following addressing modes permits relocation without any change over in the code?
    (A)   Indirect addressing
    (B)   Indexed addressing
    (C)   PC relative addressing
    (D)   Base register addressing

91   In a multi-user database, if two users wish to update the same record at the same time, they are prevented from doing so by
    (A)   Jamming
    (B)   Password
    (C)   Documentation
    (D)   Record lock

92   The values of the attribute describes a particular_____________
    (A)   Entity set
    (B)   File
    (C)   Entity instance
    (D)   Organization

93   Which of the following relational algebraic operations is not from set theory?
    (A)   Union
    (B)   Intersection
    (C)   Cartesian product
    (D)   Select

94   Which of the following ensures the atomicity of the transaction?
    (A)   Transaction management component of DBMS
    (B)   Application Programmer
    (C)   Concurrency control component of DBMS
    (D)   Recovery management component of DBMS

95   If both the functional dependencies: X->Y and Y->X hold for two attributes X and Y then the relationship between X and Y is
    (A)   M:N
    (B)   M:1
    (C)   01:01
    (D)   1:M

96   What will be the number of columns and rows respectively obtained for the operation, AB, if A B are Base union compatible and all the rows of a are common to B? Assume A has 4 columns and 10 rows; and B has 4 columns and 15 rows
    (A)   4,0
    (B)   0,0
    (C)   4,5
    (D)   8,5

97   For correct behaviour during recovery, undo and redo operation must be
    (A)   Commutative
    (B)   Associative
    (C)   Idempotent
    (D)   Distributive

98   Which of the following is not a consequence of non-normalized database?
    (A)   Update Anomaly
    (B)   Insertion Anomaly
    (C)   Redundancy
    (D)   Lost update problem

99   The part of a database management system which ensures that the data remains in a consistent state is
    (A)   Authorization and integrity manager
    (B)   Buffer manager
    (C)   Transaction manager
    (D)   File manager

100   Relationships among relationships can be represented in an-E-R model using
    (A)   Aggregation
    (B)   Association
    (C)   Weak entity sets
    (D)   Weak relationship sets

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