RDBMS Multiple Choice Questions on “Transaction Isolation”.
1. A transaction that performs only one operation is called as a _________
a) Partial schedule
b) Complete schedule
c) Dependent schedule
d) Independent schedule
Answer: a
Clarification: A transaction that performs only one operation is called as a partial schedule because we don’t include commit or rollback operations on them.
2. The phenomenon in which one failure leads to a series of transaction rollbacks is called as ________
a) Cascading rollback
b) Cascadeless rollback
c) Cascade cause
d) None of the mentioned
Answer: a
Clarification: The phenomenon in which one failure leads to a series of transaction rollbacks is called as cascading rollback. B=It is named so because one failure causes the rollback of several other transactions serially.
3. State true or false: Every cascadeless schedule is also recoverable
a) True
b) False
Answer: a
Clarification: Every cascadeless schedule is also recoverable because in a cascadeless schedule, the commit operations occur in the same sequence as that of write and read operations of two transactions respectively.
4. A ___________ is one where, for each pair of transactions Ti and Tj such that Tj reads a data item previously written by Ti , the commit operation of Ti appears before the commit operation of Tj
a) Partial schedule
b) Dependent schedule
c) Recoverable schedule
d) None of the mentioned
Answer: c
Clarification: A Recoverable schedule is one where, for each pair of transactions Ti and Tj such that Tj reads a data item previously written by Ti , the commit operation of Ti appears before the commit operation of Tj.
5. State true or false: Transactions can only run serially
a) True
b) False
Answer: b
Clarification: Transactions are safer run serially but can also be run concurrently.
6. Which of the following are the advantages of transaction concurrency?
a) Increased throughput
b) Increased utilization
c) Reduces average response time
d) All of the mentioned
Answer: d
Clarification: Concurrency in transactions allow increased throughput, utilization. They also reduce average response time.
7. The average time for a transaction to be completed after it has been submitted is called as __________
a) Minimum response time
b) Average response time
c) Average reaction time
d) Minimum reaction time
Answer: b
Clarification: The average time for a transaction to be completed after it has been submitted is called as Average response time. This gets decreased when concurrency is used in transactions.
8. If a schedule is equivalent to a serial schedule, it is called as a _________
a) Serializable schedule
b) Equivalent schedule
c) Committed schedule
d) None of the mentioned
Answer: a
Clarification: If a schedule is equivalent to a serial schedule, it is called as a Serializable schedule.
9. Which of the following is not a type of a schedule?
a) Partial schedule
b) Dependent schedule
c) Recoverable schedule
d) None of the mentioned
Answer: d
Clarification: All of the mentioned schedules i.e. partial schedule, dependent schedule, recoverable schedule are different types of schedules.