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George Wilkinson
2024-02-06 16:37:38 +00:00
parent 7f740ba87a
commit 17617d5ab3
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Semester 2/Database Systems/Week 4/Week 4 Database Systems.md
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@@ -40,7 +40,7 @@ Concurrency control is needed to properly ensure database integrity and consiste
Since one person is updating data, the operation may be conflicting if another person tries to access the value of the data, depending on the time at which the operations coincide.
4. Illustrate your answer using the example of an on-line railway seat reservation system. Assume that the railway seat reservation system must ensure that a particular seat on a particular train journey is not reserved by more than one passenger.
If person A tries to purchase a seat on a train, and person B tries to check if a seat is available at the same time, person B will be able to book the same seat if both operations are concurrent.
If person A tries to purchase a seat on a train, and person B tries to check if a seat is available at the same time, person B will be able to book the same seat if both operations are concurrent.
5. Which component of the DBMS takes responsibility for the isolation property of database transactions?
Concurrency Control
@@ -59,7 +59,7 @@ At least one writes the item
T1 and T2 conflict as T2 writes data before T1 has completed.
( 6 conflicts )
T1 and T2 conflict as T1's write operation is overwritten by T2's write operation before either transaction is complete.
( 2 conficts )
( 2 conflicts )
T1 and T2 conflict as T1's write for X is overwritten by T2's write for X before either transaction is complete
( 2 conflicts )
T1 and T2 conflict as T1's write operation is overwritten by T2's write operation before either transaction is complete.