Practice Library
All MCQs
Browse exam-wise, subject-wise, and country-wise MCQs with explanations.
Choose an option to check your answer.
A.
a data type that cannot be queried
B.
a physical page size chosen by the OS
C.
a user-defined or structured type that can represent nested or composite values
D.
a password stored inside a table
Show Answer
Correct Answer: C. a user-defined or structured type that can represent nested or composite values
Explanation:
This statement is correct because complex data type in object-relational databases means that a user-defined or structured type that can represent nested or composite values.
Choose an option to check your answer.
A.
all records are compressed into one byte
B.
only metadata is stored on disk
C.
related records that are often accessed together are stored near each other
D.
each row is stored in a different database
Show Answer
Correct Answer: C. related records that are often accessed together are stored near each other
Explanation:
The correct answer explains clustered file organization in the context of File Organization.
Choose an option to check your answer.
A.
a sequential log for transaction recovery
B.
a password hashing mechanism
C.
a lock that blocks all readers permanently
D.
a balanced tree index in which data pointers are commonly stored at leaf level
Show Answer
Correct Answer: D. a balanced tree index in which data pointers are commonly stored at leaf level
Explanation:
B+ tree index is used in Advanced DBMS because a balanced tree index in which data pointers are commonly stored at leaf level.
Choose an option to check your answer.
A.
all database users work offline
B.
transactions are physically stored on separate disks only
C.
concurrent transactions should not interfere in a way that violates correctness
D.
tables are separated from indexes
Show Answer
Correct Answer: C. concurrent transactions should not interfere in a way that violates correctness
Explanation:
This statement is correct because isolation means that concurrent transactions should not interfere in a way that violates correctness.
Choose an option to check your answer.
A.
a copy of the system catalog
B.
a log table used only for crashes
C.
a table that contains only one column
D.
a table-valued attribute that can store multiple related values within a row structure
Show Answer
Correct Answer: D. a table-valued attribute that can store multiple related values within a row structure
Explanation:
The correct answer explains nested table in object-relational systems in the context of Advance Data Models.
Choose an option to check your answer.
A.
all records are compressed into one byte
B.
each row is stored in a different database
C.
related records that are often accessed together are stored near each other
D.
only metadata is stored on disk
Show Answer
Correct Answer: C. related records that are often accessed together are stored near each other
Explanation:
clustered file organization is used in Advanced DBMS because related records that are often accessed together are stored near each other.
Choose an option to check your answer.
A.
a lock that blocks all readers permanently
B.
a sequential log for transaction recovery
C.
a password hashing mechanism
D.
a balanced tree index in which data pointers are commonly stored at leaf level
Show Answer
Correct Answer: D. a balanced tree index in which data pointers are commonly stored at leaf level
Explanation:
This statement is correct because B+ tree index means that a balanced tree index in which data pointers are commonly stored at leaf level.
Choose an option to check your answer.
A.
uncommitted changes are saved permanently
B.
data is deleted after every commit
C.
committed changes survive crashes and system failures
D.
read-only queries are blocked forever
Show Answer
Correct Answer: C. committed changes survive crashes and system failures
Explanation:
The correct answer explains durability in the context of Transactions.
Choose an option to check your answer.
A.
a table-valued attribute that can store multiple related values within a row structure
B.
a table that contains only one column
C.
a log table used only for crashes
D.
a copy of the system catalog
Show Answer
Correct Answer: A. a table-valued attribute that can store multiple related values within a row structure
Explanation:
nested table in object-relational systems is used in Advanced DBMS because a table-valued attribute that can store multiple related values within a row structure.
Choose an option to check your answer.
A.
all records are compressed into one byte
B.
each row is stored in a different database
C.
only metadata is stored on disk
D.
related records that are often accessed together are stored near each other
Show Answer
Correct Answer: D. related records that are often accessed together are stored near each other
Explanation:
This statement is correct because clustered file organization means that related records that are often accessed together are stored near each other.
Choose an option to check your answer.
A.
an index useful only for unique primary keys with many values
B.
a mechanism that replaces normalization
C.
a file format for storing images only
D.
an index using bit vectors, useful for low-cardinality attributes
Show Answer
Correct Answer: D. an index using bit vectors, useful for low-cardinality attributes
Explanation:
The correct answer explains bitmap index in the context of File Organization.
Choose an option to check your answer.
A.
read-only queries are blocked forever
B.
uncommitted changes are saved permanently
C.
data is deleted after every commit
D.
committed changes survive crashes and system failures
Show Answer
Correct Answer: D. committed changes survive crashes and system failures
Explanation:
durability is used in Advanced DBMS because committed changes survive crashes and system failures.
