Discuss Consistency and Isolation property of a transaction
Question
Discuss Consistency and Isolation property of a transaction
Solution
Consistency and Isolation are two of the four main properties (ACID) that guarantee that database transactions are processed reliably.
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Consistency: This property ensures that a transaction brings the database from one valid state to another, maintaining the integrity constraints. In other words, a transaction is a correct transformation of the state. The consistency property doesn't check the consistency of the transaction itself but it checks the state of the system before and after the transaction. If the system was in a consistent state before the transaction and the transaction is successful, the system should be in a consistent state after the transaction as well.
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Isolation: This property ensures that the concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially, i.e., one after the other. Providing isolation is the main goal of concurrency control. If a transaction is executed in isolation, the partial results of incomplete transactions are not visible to others. This is done by locking the data items that are being read or written by the transaction.
In summary, Consistency and Isolation are crucial properties of a transaction in a database system. Consistency ensures the database remains in a valid state before and after a transaction, while Isolation ensures that each transaction is executed in a manner that is independent of other transactions.
Similar Questions
What does the isolation property of transactions aim to prevent?Hardware failuresData inconsistenciesConcurrent access issuesDatabase corruptionReview AnswerNext
Which of the following is not a property of a transaction in a DBMS?Select one:a. Isolationb. Atomicityc. Consistencyd. Uniqueness
Select one:a.The data item X cannot be accessed by any other transaction T2 until the transaction T1 is completed and the data item X is used by the transaction T1.b.By using the data used during a transaction, the second transaction will not be able to use it until the first has been executed.c. All of the aboved.It enforced the isolation property via its concurrency control subsystem.
Atomicity. A transaction is an atomic unit of processing; it should either beperformed in its entirety or not performed at all.■ Consistency preservation. A transaction should be consistency preserving,meaning that if it is completely executed from beginning to end withoutinterference from other transactions, it should take the database from oneconsistent state to another.■ Isolation. A transaction should appear as though it is being executed in iso-lation from other transactions, even though many transactions are executing7Undo and redo are discussed more fully in Chapter 23.21.4 Characterizing Schedules Based on Recoverability 755concurrently. That is, the execution of a transaction should not be interferedwith by any other transactions executing concurrently.■ Durability or permanency. The changes applied to the database by a com-mitted transaction must persist in the database. These changes must not belost because of any failure.
Which of the following properties ensures that once a transaction commits, its results are permanent?Question 12Select one:A.FlexibilityB.DurabilityC.IsolationD.AtomicityE.Consistency
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