What does ACID mean in DATABASES

ACID stands for Automatic Consistency Integration of Database. It is a set of database transaction rules that helps maintain data accuracy within databases by protecting against data corruption and ensuring successful transactions be performed successfully or rolled back if any errors occur.

ACID ensures data integrity and consistency when performing transactions by following certain rules to guarantee that operations are properly executed on the database and that no data is lost or corrupted during the process. It also makes sure all changes to the database are stored in a safe manner, preventing errors from occurring due to bugs, power failures, or other unexpected events.

In order for a transaction to succeed, it must satisfy four key principles known as Atomicity, Consistency, Isolation, and Durability (ACID). Atomicity requires that all changes made during a transaction are committed together in an "all-or-nothing" manner. Consistency guarantees that data meets any constraints placed upon it, such as requiring unique values in certain columns. Isolation ensures that each transaction operates independently from other transactions running concurrently on the same database. Durability guarantees that any changes made during a successful transaction will remain persistent even after system crashes or power outages.

Atomicity guarantees that all steps in a given transaction are completed either fully or not at all. This means that if one step fails, then the entire operation fails without leaving behind partial results or corrupting your data.

Consistency ensures that any new change made to the database adheres to all data integrity constraints already established on the system. This means any new values added will not violate schema validity checks such as null values when they not allowed or foreign key constraints being violated due to incorrect references between tables.

Isolation prevents concurrent executions of transactions from interfering with one another while running concurrently by making sure they complete independently from one another without being affected by any external conditions like locks placed on tables by other users.

Durability makes sure all successful transactions become permanently stored into the database so future read operations will pick up those changes without needing manual intervention from administrators nor having intermediate states where some results might not reflect correctly.

Yes! You can use multiple databases with ACID enabled but you'll need to make sure you properly configure them prior so the rules associated with each are respected by whatever application layer needs access to them.

Databases with ACID enabled are very secure since they guarantee complete transactional safety through rules like Atomicity and Durability which help shield against malicious intent and accidental errors caused by things like hardware failure or power outages.