Isolation in the sense of ACID means that concurrently executing transactions are isolated from each other: they cannot step on each other’s toes. The classic database textbooks formalize isolation as serializability, which means that each transaction can pretend that it is the only transaction running on the entire database. The database ensures that when the transactions have committed, the result is the same as if they had run serially (one after another), even though in reality they may have run concurrently [10].
