Editing ACID (section)

{{Short description|Robustness properties for database transactions}}
{{Other uses|Acid (disambiguation)}}
{{refimprove|date=May 2018}}
In [[computer science]], '''ACID''' ([[atomicity (database systems)|atomicity]], [[consistency (database systems)|consistency]], [[isolation (database systems)|isolation]], [[durability (database systems)|durability]]) is a set of properties of [[database transaction]]s intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of [[database]]s, a sequence of database operations that satisfies the ACID properties (which can be perceived as a single logical operation on the data) is called a ''transaction''. For example, a transfer of funds from one bank account to another, even involving multiple changes such as debiting one account and crediting another, is a single transaction.

In 1983,<ref>{{Cite journal |last1=Haerder |first1=T. |author-link1=Theo Härder |last2=Reuter |first2=A. |author-link2=Andreas Reuter |doi = 10.1145/289.291 |title= Principles of transaction-oriented database recovery |journal= ACM Computing Surveys |volume=15 |issue=4 |page=287 |year=1983|s2cid=207235758 }}</ref> [[Andreas Reuter]] and [[Theo Härder]] coined the acronym ''ACID'', building on earlier work by [[Jim Gray (computer scientist)|Jim Gray]]<ref>{{cite conference |last=Gray |first=Jim |author-link=Jim Gray (computer scientist) |date=September 1981 |title=The Transaction Concept: Virtues and Limitations |url=http://research.microsoft.com/~gray/papers/theTransactionConcept.pdf |conference= |location=Cupertino, California |publisher=[[Tandem Computers]] |pages=144–154 |access-date=March 27, 2015 |book-title=Proceedings of the 7th International Conference on Very Large Databases}}</ref> 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 management system|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).<ref>{{cite book |last1=Gray |first1=Jim |author-link1=Jim Gray (computer scientist) |first2=Andreas |last2=Reuter |author-link2=Andreas Reuter |title=Distributed Transaction Processing: Concepts and Techniques |publisher=[[Morgan Kaufmann]] |date=1993 |isbn=1-55860-190-2 |url-access=registration |url=https://archive.org/details/transactionproce0000gray }}</ref>

BASE stands for basically available, soft state, and [[Eventual consistency|eventually consistent]]: the acronym highlights that BASE is opposite of ACID, like their chemical equivalents.<ref>{{Cite web |title=ACID vs BASE Databases - Difference Between Databases - AWS |url=https://aws.amazon.com/compare/the-difference-between-acid-and-base-database/ |access-date=2025-03-24 |website=Amazon Web Services, Inc. |language=en-US}}</ref> ACID databases prioritize [[Consistency (database systems)|consistency]] over '''availability''' — the whole [[Database transaction|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'''.<ref>{{Cite web |title=ACID vs BASE Databases - Difference Between Databases - AWS |url=https://aws.amazon.com/compare/the-difference-between-acid-and-base-database/ |access-date=2025-03-24 |website=Amazon Web Services, Inc. |language=en-US}}</ref>