What is a relational algebra expression to find all tuples in R that are
not in S?
a) R ∪ S
b) R ∩ S
c) R - S
d) R × S - ANSWERS-Correct Answer: c
Which property of transactions ensures that intermediate states of a
transaction are not visible to other transactions?
a) Atomicity
b) Consistency
c) Isolation
d) Durability - ANSWERS-Correct Answer: c
What is the degree of a relation?
a) The number of tuples in the relation.
b) The number of candidate keys in the relation.
c) The maximum value in an attribute of the relation.
d) The number of attributes in the relation. - ANSWERS-Correct
Answer: d
,When designing a database, why is it important to achieve lossless
decomposition?
a) To ensure that no information is lost when relations are joined.
b) To reduce the storage space required by the database.
c) To improve query execution speed.
d) To remove all functional dependencies. - ANSWERS-Correct
Answer: a
What is the primary advantage of using secondary storage for
databases?
a) It is faster than primary storage.
b) It provides non-volatile storage for large amounts of data.
c) It is more expensive than primary storage.
d) It eliminates the need for indexing. - ANSWERS-Correct Answer:
b
Which of the following storage mediums is typically used for
database backups?
a) Primary storage
b) Cache memory
c) Tertiary storage
d) Flash memory - ANSWERS-Correct Answer: c
What does the term "access time" for a disk include?
a) Seek time, rotational delay, and block transfer time.
, b) Transfer time and cache latency.
c) Seek time and RAM speed.
d) Rotational delay and cache retrieval time. - ANSWERS-Correct
Answer: a
What is "seek time" in the context of disk storage?
a) The time to rotate the disk to the desired block.
b) The time required to move the read/write head to the target track.
c) The time to transfer data from the disk to memory.
d) The time to retrieve data from cache memory. - ANSWERS-
Correct Answer: b
What is the formula for calculating rotational delay?
a) 1 / Rotational speed.
b) 2 * Rotational speed.
c) 1 / (2 * Rotational speed).
d) Seek time + Block transfer time. - ANSWERS-Correct Answer: c
Which type of file organization involves storing records in the order
they are inserted?
a) Ordered file
b) Indexed-sequential file
c) Hashed file
d) Unordered file (Heap) - ANSWERS-Correct Answer: d