Which database transaction property ensures that individual transactions are executed only once and either succeed...

Database transactions follow the ACID properties:

Atomicity → Ensures that each transaction is treated as a single “all-or-nothing” unit of work. Either the entire transaction is completed, or none of it is applied. This guarantees that transactions are executed only once and rolled back completely if they fail.

Consistency → Ensures that a transaction brings the database from one valid state to another, preserving integrity constraints.

Isolation → Ensures that concurrent transactions do not interfere with each other.

Durability → Ensures that once a transaction is committed, it remains permanent even in case of system failure.

Thus, the correct property here is Atomicity.

Microsoft Reference: ACID properties in databases