ACID

For other uses, see Acid (disambiguation).

In computer science, ACID (atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. For example, a transfer of funds from one bank account to another, involving multiple changes such as debiting one account and crediting another, is a single transaction.

In 1983, Andreas Reuter and Theo Härder coined the acronym ACID, building on earlier work by Jim Gray who named atomicity, consistency, and durability, but not isolation, when characterizing the transaction concept. These four properties are the major guarantees of the transaction paradigm, which has influenced many aspects of development in database systems.

According to Gray and Reuter, the IBM Information Management System supported ACID transactions as early as 1973 (although the acronym was created later).

BASE stands for basically available, soft state, and eventually consistent: the acronym highlights that BASE is opposite of ACID, like their chemical equivalents. ACID databases prioritize consistency over availability — the whole transaction fails if an error occurs in any step within the transaction; in contrast, BASE databases prioritize availability over consistency: instead of failing the transaction, users can access inconsistent data temporarily: data consistency is achieved, but not immediately. A database either leans towards ACID or BASE, but it cannot be both (according to CAP theorem). For example, SQL databases (like MySQL, PostgreSQL, AWS RedShift) are structured over the ACID model, while NoSQL databases (like DynamoDB or MongoDB) use the BASE architecture. However, some NoSQL databases might exhibit certain ACID traits.

This article is issued from Wikipedia. The text is available under Creative Commons Attribution-Share Alike 4.0 unless otherwise noted. Additional terms may apply for the media files.