ACID

Stands for Atomicity, Consistency, Isolation, Durability These are the four primary attributes common to any transaction: Atomicity. In a transaction involving two or more discrete pieces of information, either all of the pieces are committed or none are Consistency. A transaction either creates a new and valid state of data or, if any failure occurs, returns all data to the state before the transaction was started Isolation. A transaction in process and not yet committed must remain isolated from any other transaction Durability. Committed data are saved by the system so that, even in the event of a failure and system restart, the data are available in their correct state The ACID concept is described in ISO/IEC 10026-1:1992 Section 4. Each of these attributes can be measured against a benchmark. In general, however, a transaction manager or monitor is designated to implement the ACID concept. In a distributed system, one way to achieve ACID is to use a two-phase commit (2PC), which ensures either that all involved sites must commit to completing the transaction or that none do, and the transaction is rolled back