ACID (database)

This means that e.g. if you do an UPDATE query on multiple rows, and power goes out half way, either all update, or none update.

This is different from isolation, which considers instead what can or cannot happen when multiple queries are running in parallel.

Determines what can or cannot happen when multiple queries are running in parallel.

See Section "SQL transaction isolation level" for the most common context under which this is discussed: SQL.