When a transaction updates a row, it puts a lock so that no one can update the same row until it commits. When another transaction issues an update to the same row, it waits until the first one either commits or rolls back. After the first transaction performs a commit or rollback, the update by the second transaction is executed immediately, since the lock placed by the first transaction is now gone. How exactly does this locking mechanism work? Several questions come to mind in this context:When a transaction updates a row, it puts a lock
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How Oracle Locking Works - First_PlsSmile的专栏
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