What are transaction properties?

Transactions must have four properties recalled with the acronym ACID: Atomicity, Consistency, Isolation and Durability.

• Atomicity is "all or nothing" operation wherein, for example, a transaction consisting of a debit to one account and a credit to another is not committed unless both operations are successful. Typically, atomicity is provided by the database management system.

• Consistency reflects the state of the system. A system is always consistent based upon the state invariants and transactions give the opportunity to write code that checks the consistency of the state.

• Isolation keeps operations on shared data invisible across transactions.

• Durability guarantees the effect of completed transaction are permanent and are not lost.