Serializability in ACID Property

C.

Isolation - The isolation 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.

For CISA exam you should know below information about ACID properties in DBMS: Atomicity - Atomicity requires that each transaction is "all or nothing": if one part of the transaction fails, the entire transaction fails, and the database state is left unchanged.

An atomic system must guarantee atomicity in each and every situation, including power failures, errors, and crashes.

To the outside world, a committed transaction appears (by its effects on the database) to be indivisible ("atomic"), and an aborted transaction does not happen.

Consistency - The consistency property ensures that any transaction will bring the database from one valid state to another.

Any data written to the database must be valid according to all defined rules, including but not limited to constraints, cascades, triggers, and any combination thereof.

This does not guarantee correctness of the transaction in all ways the application programmer might have wanted (that is the responsibility of application-level code) but merely that any programming errors do not violate any defined rules.

Isolation - The isolation 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.

Depending on concurrency control method, the effects of an incomplete transaction might not even be visible to another transaction.

[citation needed] Durability - Durability means that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors.

In a relational database, for instance, once a group of SQL statements execute, the results need to be stored permanently (even if the database crashes immediately thereafter)

To defend against power loss, transactions (or their effects) must be recorded in a non-volatile memory.

The following were incorrect answers: Consistency - The consistency property ensures that any transaction will bring the database from one valid state to another.

Any data written to the database must be valid according to all defined rules, including but not limited to constraints, cascades, triggers, and any combination thereof.

This does not guarantee correctness of the transaction in all ways the application programmer might have wanted (that is the responsibility of application-level code) but merely that any programming errors do not violate any defined rules.

Durability - Durability means that once a transaction has been committed, it will remain so, even in the event of power loss, crashes, or errors.

Atomicity requires that each transaction is "all or nothing": if one part of the transaction fails, the entire transaction fails, and the database state is left unchanged.

The ACID (Atomicity, Consistency, Isolation, Durability) properties are essential properties of database transactions that ensure the accuracy, reliability, and consistency of data within a database system.

The property that ensures that concurrent execution of transactions results in a system state that would be obtained if transactions were executed serially is the Isolation property.

Isolation ensures that each transaction is executed in complete isolation from other concurrent transactions. The isolation property of a database transaction ensures that a transaction is not affected by the changes made by other transactions until the transaction is completed.

In other words, the isolation property ensures that concurrent transactions do not interfere with each other, and the end result of the concurrent execution of multiple transactions is the same as if they were executed serially one after the other.

Isolation is critical in multi-user database systems where multiple transactions can occur simultaneously. Without proper isolation, concurrent transactions could interfere with each other, leading to data inconsistencies, lost updates, and other issues.

Therefore, Isolation is the ACID property in DBMS that 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.