1
A _________ consists of a sequence of query and/or update statements.
Correct Answer
Transaction
ā MCQ PRACTICE
Database Management Systems Unit 4
Practice objective questions for quick revision and examination preparation. Try answering each question before revealing the answer.
Database Management Systems - Unit-4
2
Which of the following makes the transaction permanent in the database?
Correct Answer
Commit
3
In order to undo the work of transaction after last commit which one should be used?
Correct Answer
Rollback
4
What is ACID properties of Transactions?
Correct Answer
Atomicity, Consistency, Isolation, Durability
5
In order to maintain the consistency during transactions, database provides
Correct Answer
Atomic
6
Database locking concept is used to solve the problem of
Correct Answer
All of the above
7
Execution of transaction in isolation preserves the _________ of a database
Correct Answer
Consistency
8
A lock that allows concurrent transactions to access different rows of the same table is known as a
Correct Answer
Field-level lock
9
A system is in a ______ state if there exists a set of transactions such that every transaction in the set is waiting for another transaction in the set.
Correct Answer
Deadlock
10
Which of the following occurs when a transaction rereads data and finds new rows that were inserted by a command transaction since the prior read?
Correct Answer
Phantom read
11
Which of the following systems is responsible for ensuring durability?
Correct Answer
Recovery system
12
Which of the following systems is responsible for ensuring isolation?
Correct Answer
Concurrency control system
13
A transaction for which all committed changes are permanent is called:
Correct Answer
durable
14
Transaction management ensures ____________ and __________ properties.
Correct Answer
Atomicity and Durability
15
Concurrency control is important for which of the following reasons?
Correct Answer
To ensure data integrity when updates occur to the database in a multiuser environment
16
Locking may cause which of the following problems?
Correct Answer
Deadlock
17
Execution of transaction in isolation preserves the _________ of a database
Correct Answer
Consistency
18
State true or false: If I = read(Q) and J = write(Q) then the order of I and J does not matter.
Correct Answer
False
19
If a schedule is equivalent to a serial schedule, it is called as a _________
Correct Answer
Serializable schedule
20
________ allows only committed data to be read and further requires that no other transaction is allowed to update it between two reads of a data item by a transaction.
Correct Answer
Repeatable read
21
When is a timestamp allotted
Correct Answer
When execution begins
22
I and J are _________ if they are operations by different transactions on the same data item, and at least one of them is a write operation.
Correct Answer
Conflicting
23
If a schedule S can be transformed into a schedule Sā by a series of swaps of non-conflicting instructions, then S and Sā are
Correct Answer
Conflict equivalent
24
The set of ________ in a precedence graph consists of all the transactions participating in the schedule
Correct Answer
Vertices
Fill in the Blanks
25
Database __________ are the units in which programs read or write information.
Correct Answer
objects
26
Once the DBMS informs the user that a transaction has been successfully completed, its effects should persist even if the system crashes before all its changes are reflected on disk known as __________
Correct Answer
durability
27
__________ is the initial state of a transaction.
Correct Answer
Active state
28
__________ state occurs after the discovery that normal execution can no longer proceed.
Correct Answer
Failed
29
Transaction-processing systems usually allow multiple transactions to run concurrently (at the same time) known as __________
Correct Answer
concurrent execution of transactions
30
Users are responsible for ensuring transaction __________
Correct Answer
consistency
31
The __________ locking protocol ensures serializability.
Correct Answer
two-phase
32
__________ protocols ensure that the system will never enter into a deadlock state.
Correct Answer
Deadlock prevention
33
When a deadlock is detected, some transaction will have to be rolled back to break the __________
Correct Answer
deadlock
34
A transaction is an execution of a user program and is seen by the DBMS as a __________ or list of actions.
Correct Answer
series