Which type of transaction schedules can be transformed into a serial schedule without changing the outcome, ensuring consistency?

• A. Conflict Serializable Schedules
• B. Recoverable Schedules
• C. Non-serializable
• D. Serial Schedules

Answer: (A)

In a database, you can interleave operations from different transactions. A schedule is conflict-serializable if you can reorder those interleaved operations, by swapping adjacent operations that do not conflict, to obtain a serial schedule that produces the same final state. Conflicts arise when two operations from different transactions access the same data item and at least one of them is a write; reads on the same item from different transactions do not conflict, but any pair involving a write does.

This type is the best answer because it guarantees that there exists a serial order yielding the same results, so the outcome remains consistent despite the interleaving. The other concepts address different concerns: recoverable schedules focus on abort and cascading effects, non-serializable schedules cannot be rearranged into any serial schedule without changing results, and serial schedules are already in serial form with no interleaving.