Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
a table-valued attribute that can store multiple related values within a row structure
B.
a log table used only for crashes
C.
a copy of the system catalog
D.
a table that contains only one column
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Correct Answer: A. a table-valued attribute that can store multiple related values within a row structure
Explanation:
This statement is correct because nested table in object-relational systems means that a table-valued attribute that can store multiple related values within a row structure.
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A.
an index created only for backup files
B.
an index built on a file ordered by the primary key
C.
a temporary variable inside a trigger
D.
a security role assigned to all users
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Correct Answer: B. an index built on a file ordered by the primary key
Explanation:
The correct answer explains primary index in the context of File Organization.
Choose an option to check your answer.
A.
an index using bit vectors, useful for low-cardinality attributes
B.
a mechanism that replaces normalization
C.
a file format for storing images only
D.
an index useful only for unique primary keys with many values
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Correct Answer: A. an index using bit vectors, useful for low-cardinality attributes
Explanation:
bitmap index is used in Advanced DBMS because an index using bit vectors, useful for low-cardinality attributes.
Choose an option to check your answer.
A.
committed changes survive crashes and system failures
B.
read-only queries are blocked forever
C.
uncommitted changes are saved permanently
D.
data is deleted after every commit
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Correct Answer: A. committed changes survive crashes and system failures
Explanation:
This statement is correct because durability means that committed changes survive crashes and system failures.
Choose an option to check your answer.
A.
BLOBs and CLOBs are used to store large binary or character data
B.
large objects are a type of transaction lock
C.
large files cannot be stored in databases
D.
large data must always be stored in primary keys
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Correct Answer: A. BLOBs and CLOBs are used to store large binary or character data
Explanation:
The correct answer explains large object management in the context of Advance Data Models.
Choose an option to check your answer.
A.
an index built on a file ordered by the primary key
B.
a temporary variable inside a trigger
C.
an index created only for backup files
D.
a security role assigned to all users
Show Answer
Correct Answer: A. an index built on a file ordered by the primary key
Explanation:
primary index is used in Advanced DBMS because an index built on a file ordered by the primary key.
Choose an option to check your answer.
A.
an index using bit vectors, useful for low-cardinality attributes
B.
a file format for storing images only
C.
a mechanism that replaces normalization
D.
an index useful only for unique primary keys with many values
Show Answer
Correct Answer: A. an index using bit vectors, useful for low-cardinality attributes
Explanation:
This statement is correct because bitmap index means that an index using bit vectors, useful for low-cardinality attributes.
Choose an option to check your answer.
A.
transactions execute only on multiple distributed sites
B.
transactions execute one after another without interleaving operations
C.
all locks are released before reading
D.
every query is optimized using only sorting
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Correct Answer: B. transactions execute one after another without interleaving operations
Explanation:
The correct answer explains serial schedule in the context of Transactions.
Choose an option to check your answer.
A.
large data must always be stored in primary keys
B.
large objects are a type of transaction lock
C.
large files cannot be stored in databases
D.
BLOBs and CLOBs are used to store large binary or character data
Show Answer
Correct Answer: D. BLOBs and CLOBs are used to store large binary or character data
Explanation:
large object management is used in Advanced DBMS because BLOBs and CLOBs are used to store large binary or character data.
Choose an option to check your answer.
A.
an index created only for backup files
B.
an index built on a file ordered by the primary key
C.
a security role assigned to all users
D.
a temporary variable inside a trigger
Show Answer
Correct Answer: B. an index built on a file ordered by the primary key
Explanation:
This statement is correct because primary index means that an index built on a file ordered by the primary key.
Choose an option to check your answer.
A.
authentication, compression, integrity, and deletion define file organization
B.
atomicity, consistency, isolation, and durability define reliable transaction behavior
C.
availability, caching, insertion, and deletion define SQL syntax
D.
accuracy, coding, indexing, and distribution define database tuning
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Correct Answer: B. atomicity, consistency, isolation, and durability define reliable transaction behavior
Explanation:
The correct answer explains ACID properties in the context of Transactions.
Choose an option to check your answer.
A.
all locks are released before reading
B.
transactions execute only on multiple distributed sites
C.
every query is optimized using only sorting
D.
transactions execute one after another without interleaving operations
Show Answer
Correct Answer: D. transactions execute one after another without interleaving operations
Explanation:
serial schedule is used in Advanced DBMS because transactions execute one after another without interleaving operations.
