Oracle 11G OCP 1Z0-053 52

（52）You have the following requirements in relation to the detection of block corruption for your database instance:

Check for logical self-consistency of data blocks when modified in memory.

Checksums are calculated before and after the block change.

Checks are performed for the lost writes to the physical standby database.

Which method would help you perform the above checks automatically?

A. Set the DB_SECUREFILE parameter to PERMITTED.

B. Set the DB_ULTRA_SAFE parameter to DATA_ONLY.

C. Set the DB_LOCK_CHECKSUM parameter to TYPICAL.

D. Set the DB_LOST_WRITE_PROTECT parameter to TYPICAL.

答案：（B）

解析：

該引數設定其它引數的預設值來控制保護的級別

DB_ULTRA_SAFE = {OFF | DATA_ONLY | DATA_AND_INDEX}

1. OFF,當DB_BLOCK_CHECKING, DB_BLOCK_CHECKSUM, DB_LOST_WRITE_PROTECT任何一個被顯示設定時,不會有任何改變.

2. DATA_ONLY

    DB_BLOCK_CHECKING = MEDIUM

    DB_BLOCK_CHECKSUM = FULL

    DB_LOST_WRITE_PROTECT = TYPICAL

3. DATA_AND_INDEX

    DB_BLOCK_CHECING = FULL

    DB_BLOCK_CHECKSUM = FULL

    DB_LOST_WRITE_PROTECT = TYPICAL

來自 “ ITPUB部落格 ” ，連結：http://blog.itpub.net/17013648/viewspace-1250886/，如需轉載，請註明出處，否則將追究法律責任。