Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
transforming a distributed query into operations on fragments at relevant sites
B.
forcing every query to run centrally
C.
turning all local data into passwords
D.
deleting remote data after a query
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Correct Answer: A. transforming a distributed query into operations on fragments at relevant sites
Explanation:
data localization is used in Advanced DBMS because transforming a distributed query into operations on fragments at relevant sites.
Choose an option to check your answer.
A.
a model that cannot store nested data
B.
a model used only for transaction logs
C.
a NoSQL model that stores semi-structured documents such as JSON or BSON
D.
a model that stores only fixed two-column tables
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Correct Answer: C. a NoSQL model that stores semi-structured documents such as JSON or BSON
Explanation:
This statement is correct because document database means that a NoSQL model that stores semi-structured documents such as JSON or BSON.
Choose an option to check your answer.
A.
users can access data without knowing its physical site location
B.
users must specify exact disk addresses
C.
queries cannot access remote data
D.
all data must be stored in one location
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Correct Answer: A. users can access data without knowing its physical site location
Explanation:
location transparency is used in Advanced DBMS because users can access data without knowing its physical site location.
Choose an option to check your answer.
A.
deleting remote data after a query
B.
forcing every query to run centrally
C.
turning all local data into passwords
D.
transforming a distributed query into operations on fragments at relevant sites
Show Answer
Correct Answer: D. transforming a distributed query into operations on fragments at relevant sites
Explanation:
This statement is correct because data localization means that transforming a distributed query into operations on fragments at relevant sites.
Choose an option to check your answer.
A.
users can access data without knowing its physical site location
B.
users must specify exact disk addresses
C.
queries cannot access remote data
D.
all data must be stored in one location
Show Answer
Correct Answer: A. users can access data without knowing its physical site location
Explanation:
This statement is correct because location transparency means that users can access data without knowing its physical site location.
Choose an option to check your answer.
A.
using only a single local lock table always
B.
coordinating concurrent transactions that access data at multiple sites
C.
running all transactions without isolation
D.
denying every remote read
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Correct Answer: B. coordinating concurrent transactions that access data at multiple sites
Explanation:
The correct answer explains distributed concurrency control in the context of Distributed Databases.
Choose an option to check your answer.
A.
users must join fragments manually every time
B.
fragments cannot be reconstructed
C.
users need not know how relations are fragmented across sites
D.
fragments must be encrypted only
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Correct Answer: C. users need not know how relations are fragmented across sites
Explanation:
The correct answer explains fragmentation transparency in the context of Distributed Databases.
Choose an option to check your answer.
A.
coordinating concurrent transactions that access data at multiple sites
B.
denying every remote read
C.
using only a single local lock table always
D.
running all transactions without isolation
Show Answer
Correct Answer: A. coordinating concurrent transactions that access data at multiple sites
Explanation:
distributed concurrency control is used in Advanced DBMS because coordinating concurrent transactions that access data at multiple sites.
Choose an option to check your answer.
A.
a table must be stored on a web domain
B.
a transaction must use two-phase commit
C.
a query must run only on Sunday
D.
an attribute value must come from a permitted domain or range
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Correct Answer: D. an attribute value must come from a permitted domain or range
Explanation:
The correct answer explains domain constraint in the context of Integrity and Security.
Choose an option to check your answer.
A.
a statement used only for sorting rows
B.
a statement used to create a backup image
C.
a statement used to start a cursor
D.
a statement used to remove privileges from users or roles
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Correct Answer: D. a statement used to remove privileges from users or roles
Explanation:
REVOKE statement is used in Advanced DBMS because a statement used to remove privileges from users or roles.
Choose an option to check your answer.
A.
drawing only conceptual ER diagrams
B.
assigning usernames to employees only
C.
deciding storage structures, indexes, partitions, and access paths for performance
D.
writing marketing content for a database product
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Correct Answer: C. deciding storage structures, indexes, partitions, and access paths for performance
Explanation:
This statement is correct because physical database design means that deciding storage structures, indexes, partitions, and access paths for performance.
Choose an option to check your answer.
A.
splitting a relation by rows only
B.
splitting a relation by columns while preserving a way to reconstruct it
C.
storing all data in one central table
D.
deleting the primary key from every fragment
Show Answer
Correct Answer: B. splitting a relation by columns while preserving a way to reconstruct it
Explanation:
The correct answer explains vertical fragmentation in the context of Distributed Databases.
