10 Questions
Explain the purpose of concurrency control in databases and provide an example of conflicting transactions.
Concurrency control in databases aims to enforce isolation among conflicting transactions, ensuring that a transaction's updates are not visible to other transactions until it is committed. An example of conflicting transactions is when T1 and T2 conflict over a data item A in a concurrent execution environment, and the existing concurrency control decides which transaction should get A and if the other transaction is rolled back or waits.
Define a lock in the context of database concurrency control.
A lock is a variable associated with a data item that describes the status of the item with respect to possible operations that can be applied to it.
What is the role of locking in the context of database concurrency control?
Locking is an operation that secures data items by controlling the access and operations that can be performed on them, thereby ensuring consistency and isolation among transactions.
How does database concurrency control help preserve database consistency through consistency-preserving execution of transactions?
Database concurrency control helps preserve database consistency by ensuring that transactions are executed in a consistent manner, and by resolving read-write and write-write conflicts, thus maintaining the overall integrity of the database.
What are the key goals of database concurrency control, and how do they contribute to the overall management of concurrent transactions?
The key goals of database concurrency control are to enforce isolation, preserve database consistency, and resolve conflicts among concurrent transactions. These goals contribute to the overall management of concurrent transactions by maintaining data integrity and ensuring that transactions are executed in a controlled and consistent manner.
Concurrency control techniques ensure that conflicting transactions are executed simultaneously without any issues.
False
A lock is a variable associated with a data item that describes the status of the item with respect to possible operations that can be applied to it.
True
Isolation refers to a transaction making its updates visible to other transactions before it is committed.
False
Database concurrency control aims to resolve read-write and write-write conflicts that may arise during concurrent execution.
True
Locking is an operation that does not play a significant role in securing data items in the context of database concurrency control.
False
Test your knowledge of database concurrency control techniques with this quiz. Explore the purpose of concurrency control and the enforcement of isolation among conflicting transactions. Topics include mutual exclusion, isolation, and preserving database consistency.
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