ACID

What Does ACID Mean? Below is a breakdown of the ACID properties, which are critical to the operations of database transactions. 🔹 Atomicity A transaction is a single unit of operation – either all its data modifications are performed, or none are. If a fault occurs during the transaction, all changes are rolled back as if the transaction never occurred. This "all or nothing" approach guarantees a database transaction is atomic. 🔹 Consistency Consistency refers to maintaining the database's integrity constraints. Any transaction will only transition the database from one valid state to another, adhering to predefined integrity rules. Unlike consistency in the CAP theorem relating to write visibility, ACID consistency focuses on the validity of transactions. 🔹 Isolation Isolation ensures concurrently executing transactions cannot view or interfere with each other's intermediate states. While complete "serializability" would run transactions sequentially, practical systems often necessitate weaker isolation levels that still protect integrity at better performance. 🔹 Durability Once committed, a transaction will persist even after system failures. This means changes are permanent and survive crashes. In distributed databases, durability involves replicating transaction data across nodes to prevent loss. – Subscribe to our weekly newsletter to get a Free System Design PDF (158 pages): https://bit.ly/496keA7