oracle 锁机制42（Oracle锁机制42）.docVIP

oracle 锁机制42（Oracle锁机制42） ORACLE lock mechanism A database is a shared resource that is used by multiple users. When multiple users concurrently access data, in the database will produce multiple transactions simultaneously access to the same data. If you do not control concurrent operations, you may read and store incorrect data and destroy the consistency of the database. Locking is a very important technique to realize concurrency control of database. When a transaction is operating on a data object, it first issues a request to the system and locks it. After locking, the transaction has a