What does ACID mean in UNCLASSIFIED

ACID stands for Atomic Consistent Isolation and Durability. It is a set of properties that guarantee a database transaction will preserve data integrity and consistency no matter what happens to the system.

ACID helps ensure data integrity by providing an all-or-nothing approach to transactions. Before any changes are made to the database, they all must either pass or fail together. This prevents any partial updates or erroneous information from being stored in the database.

Atomicity ensures that each transaction is composed of one or more individual operations that will either be committed or rolled back as an atomic unit. If one operation fails, the entire transaction is reverted and none of the operations take effect in the database.

Consistency ensures that any transitions from one valid state to another valid state are successfully completed if made concurrently. It also guarantees that if any transaction ends abruptly due to system failure or error, it can be rolled back and returned to its original state with no data loss.

Isolation means that all operations taking place within a single transaction are isolated from outside interventions until the transaction either succeeds or fails. This guarantees that other operations won't interfere with each other while they take place simultaneously within a database system.

Durability means that after a successful transaction has been executed, its changes will remain intact even if there are subsequent power failures or system crashes. Thus, durable databases guarantee reliability and accessibility of data over time even if unexpected events occur.

By using ACID, systems guarantee reliable transactions which prevents data corruptions and inconsistencies due to power outages and system errors without having to rollback individual transactions manually when such issues arise.

Yes, relational databases such as MySQL and Oracle are based on ACID principles, which ensures their reliability when coping with concurrent transactions running at the same time.

There are alternatives for ensuring database consistency like pessimistic locking or optimistic locking methods but these sacrifices concurrency performance for consistency whereas ACID provides both performance efficiency and consistency.