Lost Update
A concurrency anomaly in which one transaction overwrites another transaction's update without correctly observing or reconciling it.
Database Context
A lost update occurs when a read-modify-write sequence overwrites a concurrent change without detecting or reconciling it. Version columns, compare-and-set update predicates, explicit locking, or atomic SQL expressions can prevent the overwrite depending on the invariant being protected.
Conflict Boundary
A deliberate last-write-wins policy is a conflict-resolution rule. A lost update is normally an unintended disappearance of another transaction's state and therefore a correctness failure.