This set of RDBMS Multiple Choice Questions & Answers (MCQs) focuses on “Validation Based Protocols”.
1. The _________ requires each transaction executes in two or three different phases in its lifetime
a) Validation protocol
b) Timestamp protocol
c) Deadlock protocol
d) View protocol
View Answer
Explanation: The validation protocol requires each transaction to execute in two or three different phases in its lifetime depending on whether it is a read only or an update transaction.
2. During __________ phase, the system reads data and stores them in variables local to the transaction.
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View Answer
Explanation: During the read phase, the system reads data and stores them in variables local to the transaction. It performs all write operations on temporary local variables without updates on the actual database.
3. During the _________ phase the validation test is applied to the transaction
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View Answer
Explanation: During the validation phase, the validation test is applied to the transaction. This determines whether the transaction is allowed to proceed or not without causing a violation of serializability.
4. During the _______ phase, the local variables that hold the write operations are copied to the database
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View Answer
Explanation: During the write phase, the local variables that hold the write operations are copied to the database. Read only operations omit this phase.
5. Read only operations omit the _______ phase
a) Read phase
b) Validation phase
c) Write phase
d) None of the mentioned
View Answer
Explanation: Read only operations do not allow write operation to be performed on them. So, they omit the write phase but execute the read and validation phases.
6. Which of the following timestamp is used to record the time at which the transaction started execution?
a) Start(i)
b) Validation(i)
c) Finish(i)
d) Write(i)
View Answer
Explanation: There are three different timestamps for each transaction start(i), validation(i), finish(i). Start(i) is used to record the time at which the transaction execution started.
7. Which of the following timestamps is used to record the time when a transaction has finished its read phase?
a) Start(i)
b) Validation(i)
c) Finish(i)
d) Write(i)
View Answer
Explanation: There are three different timestamps for each transaction start(i), validation(i), finish(i). The validation phase is used to record the time at which a transaction has finished its read phase and has started its validation phase.
8. Which of the following timestamps is used to record the time when a database has completed its write operation?
a) Start(i)
b) Validation(i)
c) Finish(i)
d) Write(i)
View Answer
Explanation: There are three different timestamps for each transaction start(i), validation(i), finish(i). Finish(i) is used to record the time when a transaction has finished its write phase.
9. State true or false: Locking and timestamp ordering force a wait or rollback whenever a conflict is detected.
a) True
b) False
View Answer
Explanation: Locking and timestamp ordering force a wait or rollback whenever a conflict is detected. This property is called pessimism of locking and timestamp protocols.
10. State true or false: We determine the serializability order of validation protocol by the validation ordering technique
a) True
b) False
View Answer
Explanation: We determine the serializability order of the validation protocol by the timestamp ordering technique. There is no technique called as the validation ordering technique to determine the serializability order of the validation protocol.
Sanfoundry Global Education & Learning Series – RDBMS.
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