In order to reflect the correct state of reality in the system, a transaction should have the following properties. Either the entire sequence of operations is successful or unsuccessful. A transaction should be treated as a single unit of operation. Completed transactions are only committed and incomplete transactions are rolled back or restored to the state where it started. There is absolutely no possibility of partial work being committed.
Consistency is concerned with correctly reflecting the reality of the state of the resources.
Some of the concrete examples of consistency are referential integrity of the database, unique primary keys in tables etc. Isolation assures that transactions do not access data that is being concurrently updated. The other name for isolation is serialization. Resource managers ensure that the results of a transaction are not altered due to system failures. Inc. All Rights Reserved.