What is the role of transactions in ensuring database integrity?

Transactions in databases ensure data integrity by guaranteeing that a group of operations is executed as a single unit. If one of the operations cannot be completed, all changes are rolled back, preventing partially completed updates. This is achieved through the properties of ACID:

• Atomicity: all operations of a transaction are either fully completed or not executed at all.
• Consistency: a transaction brings the database from one valid state to another.
• Isolation: concurrent transactions do not affect each other.
• Durability: once committed, changes are saved even in case of failures.

For example, when transferring money between accounts, a transaction guarantees that the debit from one account and the credit to another happen together or not at all.