What is ACID compliance?
The presence of four components — atomicity, consistency, isolation and durability — can ensure that a database transaction is completed in a timely manner. When databases possess these components, they are said to be ACID-compliant.
Atomicity
Database transactions, like atoms, can be broken down into smaller parts. When it comes to your database, atomicity refers to the integrity of the entire database transaction, not just a component of it. In other words, if one part of a transaction doesn’t work like it’s supposed to, the other will fail as a result—and vice versa
Consistency
For any database to operate as it’s intended to operate, it must follow the appropriate data validation rules. Thus, consistency means that only data which follows those rules is permitted to be written to the database. If a transaction occurs and results in data that does not follow the rules of the database, it will be ‘rolled back’ to a previous iteration of itself (or ‘state’) which complies with the rules. On the other hand, following a successful transaction, new data will be added to the database and the resulting state will be consistent with existing rules.
Isolation
For a database, isolation refers to the ability to concurrently process multiple transactions in a way that one does not affect another.
Durability
In databases that possess durability, data is saved once a transaction is completed, even if a power outage or system failure occurs.