Question

Q4: Define transactions in DBMS. Briefly explain each of the ACID properties of a transaction [10 points]

Answer 1

Transaction:

A transaction can be considered as the unit of programs that are executed at the same time.

It is initiated by the user program in general.

ACID Properties:

To ensure the integrity of the data, the following properties are used.

Atomicity:

This states that either all the operations of a transaction are reflected to the database or none of them are reflected.

Consistency:

The execution of the transaction in isolation preserves the consistency of the database system.

Isolation:

When multiple transactions are occurring at same time, the system must ensure that for every page of transaction T1, T2 it appears that T2 has started once after T1 has executed.

Durability:

Once the transaction is completed and the changes are made to the database, these changes must be permanent.

These updated changes to the data must be stored permanently.