Question 1

Most multiuser automatically initiate and enforce locking procedures, where all locking information is managed by the lock manager.

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Question 2

-level locks are less restrictive than database-level locks, but they create traffic jams when many transactions are waiting to access the same table.

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Question 3

Although the DBMS is designed to recover a database to a previous consistent state when an interruption prevents the completion of a required set of transactions, the transactions themselves are defined by the end user or programmer and must be correct.

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Question 4

A(n) occurs when a transaction executes a query at time t1, and then it runs the same query at time t2, yielding additional rows that satisfy the query.
A) phantom read
B) dirty read
C) uncommitted dependency
D) nonrepeatable read

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Question 5

The interleaves the execution of database operations to ensure serializability.

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Question 6

Database transaction restores a database from an inconsistent state to a previously consistent state.

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Question 7

If T1 has not unlocked data item Y, T2 cannot begin; if T2 has not unlocked data item X, T1 cannot continue. Consequently, T1 and T2 each wait for the other to unlock the required data item. Such a deadlock is also known as a(n) _____.

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Question 8

What is transaction isolation and why it is important?

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Question 9

Uniqueness ensures that no equal time stamp values can exist, and ensures that time stamp values always increase.

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Question 10

As a rule, a(n) must unlock the object after its termination.

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Question 11

can take place at any of the following levels: database, table, page, row, or field.

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Question 12

To determine the appropriate order of the operations, the scheduler bases its actions on concurrency control algorithms, such as or time stamping methods.

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Question 13

The occurs when two concurrent transactions, T1 and T2, are updating the same data element and one of the updates is lost.

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Question 14

The scheduler's main job is to create a(n) of a transaction's operation, in which the interleaved executions of transactions yield the same results as if the transactions were executed in serial order.

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Question 15

The objective of control is to ensure the serializability of transactions in a multiuser database environment.

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Question 16

If a(n) is issued before the termination of a transaction, the DBMS will restore the database only for that particular transaction, rather than for all transactions, in order to maintain the durability of the previous transactions.

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Question 17

In a heavily used database management system (DBMS), the prevention and detection of constitutes an important DBMS function.

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Question 18

ensure that a disk physical failure will not impair the DBMS's ability to recover data.

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Question 19

control is important because the simultaneous execution of transactions over a shared database can create several data integrity and consistency problems.

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Question 20

The rule states that only one transaction at a time can own an exclusive lock on the same object.

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Quiz 10: Transaction Management and Concurrency Control