Final answer:
A schedule S is serializable if it is equivalent to some serial schedule of the same n transactions, ensuring that results of concurrent transactions are consistent as if they were executed in sequence.
Step-by-step explanation:
A schedule S is serializable if it is equivalent to some serial schedule of the same n transactions. Serializability is a key concept in database systems to ensure that concurrent transactions yield results that are consistent with some order of serial execution. In other words, even though transactions may be processed in parallel, a serializable schedule ensures that the transactions could be serialized—in sequence—without causing any inconsistency in the database state.
For a schedule to be considered serializable, all the concurrent transactions must align with the constraints of conflict serializability or view serializability. Conflict serializability requires that concurrent transactions are ordered in such a way that, if two transactions access the same data item and at least one is a write, they are ordered to prevent a conflict. In view serializability, the overall effect must match that of a serial execution, but the order of reads and writes can vary as long as that effect is preserved.