鎖資料列(可讀/不可讀)

MySQL Document 14.5.2.4 Locking Reads

主要分為sharedLock與lockForUpdate:

sharedLock locks only for write, lockForUpdate also prevents them from being selected

Pessimistic Locking (SELECT ... FOR UPDATE)

談到pessimistic concurrency control(Lock row for read)，實作上再Transaction內使用：

SELECT ... FOR UPDATE

則結果列將會被鎖定且不可讀，應用上可做不重複流水號等等。