The ACID model of database design is an important concept in database theory. It states four goals that a database management system must achieve: atomicity, consistency, isolation, and durability. A relational database that does not meet any of these four goals cannot be considered reliable. Conversely, a database that has these characteristics is considered ACID-compliant.

Each of the four ACID characteristics follows clearly defined standards:

Database administrators use several strategies to enforce ACID.

One strategy used to enforce atomicity and durability is write-ahead logging, where all transaction details are first written to a log that contains both redo and undo information. This approach ensures that, in the event of a database error, the database can examine the log and compare its contents to the state of the database.