WorksheetsACID Propertis , Serializability and Locks
Total questions: 20
Worksheet time: 7mins
Which property of a transaction ensures that either all operations are completed or none are?
Durability
Atomicity
Isolation
Consistency
In transaction management what does 'C' stands for?
Concurrency
Consistency
Complexity
Corelated
Which SQL command is used to undo all the changes made by a transaction?
Savepoint
Grant
Commit
Rollback
What is SAVEPOINT in transaction management?
A command to finaalize a transaction
A lock applied to prevent deadlocks
A point where the database is backed up
A marker within a transaction to roll back partially
Which type of serializability uses a precedence graph?
Conflict serializability
View serializability
Cascadeless serializability
Recoverability
In view serializability, the final (a) operation on each data item must match the serial schedule
Two operations conflict when they:
Access the same item and one is a write
Are both reads
Belong to different schedules
Access different data items
Which of the following is not a ACID property
Atomicity
Consistency
Integrity
Durability
Which schedule type ensures serializability
Non-serial
Serial
Recoverable
Cascadeless
which isolation level allows dirty reads
Read uncommited
Read commited
Repeatable
Serializable
what is a dirty read
(a)
A schedule with only read operation is
Always cyclic
Always conflict serializable
not serializable
Always non recoverable
Which operation causes a write-write conflict
R1(X),R2(X)
W1(X),W2(X)
R1(X)W2(X)
W1(X),R2(X)
Which protocol guarantees conflict serializability
Timestamp ordering
Strict 2PL
Deadlock detection
Shadow paging
Which lock allows multiple transactions to read the same data item simultaneously
Update lock
Exclusive lock
Intent exclusive lock
Shared lock
Which lock mode prevents all other locks on a data item
Exclusive lock
Read lock
Intent shared lock
Shared lock
Which of the following causes the deadlock
A transaction releasing lock early
Two transactions
holding shared locks
Two transactions waiting for each other exclusive lock
Using timestamp ordering
Even if system crashes after a commit the data remains safe according to which ACID property
(a)
Consistency ensures that after a transaction, the database is:
Faster
In a valid state
Free of locks
Serializable
Consistency is violated when:
A transaction commits
A transaction updates two tables
A transaction leaves the database in invalid state
A transaction reads the same item twice
