What is ACID (Atomicity, Consistency, Isolation, Durability)?

Overview

ACID is a framework that guarantees the reliable processing of transactions in a database. Each of the four principles plays a crucial role in maintaining the integrity of data. Atomicity ensures that transactions are all-or-nothing, meaning if one part of the transaction fails, the entire transaction fails, preventing partial updates to the database. Consistency ensures that a transaction can only bring the database from one valid state to another valid state, maintaining all predefined rules and constraints. For example, if a bank transaction moves money from one account to another, it must ensure that the total amount of money remains the same before and after the transaction. Isolation ensures that transactions occur independently without interference, so one user's transaction does not affect another user's transaction. Durability guarantees that once a transaction has been committed, it will remain so, even in the event of a system failure. This means that once you have successfully completed a transaction, such as transferring funds, that change is saved permanently. These principles are essential for applications such as banking systems, where data integrity and reliability are critical.