ACID Lock Controls – A Great Memorization Tip

The Acid model is a database lock control for relational and object oriented databases.  The purpose of it is to prevent a deadlock situation – a deadlock is when users or processes try to use a resource at the same time and are prevented from committing transactions. When implemented properly, lock controls such as ACID can help prevent deadlocks from occurring.

ACID stands for atomicity, consistency, isolation, and durability.

Atomicity ensures that all steps must occur before a transaction is completed, otherwise it is rolled back to its original state.  You can remember this by associating the “A” in Atomicity with “All or none”.  Atomicity = All or None steps

Consistency refers to transactions being consistent with rules.  Unfortunately there’s no good trick to memorizing this one, you just have to memorize “Constistent with rules”.

Isolation refers to the steps in the transaction being isolated from other processes or users, meaning they can’t see that a transaction is about to occur and that the operations are isolated until complete.  Think of the human eye and associate it with the I in i(eye)solation.  To memorize, repeat the phrase “I(eye)solation = nobody can see” so you can tie the EYE and the SEE words to remember… Durability refers to the completion of a transaction to a database, and that once committed, it must be preserved in the DB.  To memorize, repeat the phrase Durability = DB.