Oracle OCP 1Z0 053 Q495(Validate Database)

495.Which statement is true regarding the VALIDATE DATABASE command?
A. It checks the database for intrablock corruptions only.
B. It checks for block corruption in the valid backups of the database.
C. It checks the database for both intrablock and interblock corruptions.
D. It checks for only those corrupted blocks that are associated with data files.
Answer: A



參考：http://docs.oracle.com/cd/B28359_01/backup.111/b28270/glossary.htm#CHDIADHG

interblock corruption

A type of block corruption in which the corruption occurs between blocks rather than within the block itself. This type of corruption can only be logical corruption.

interblock corruption是資料塊之間的邏輯衝突

intrablock corruption

A type of block corruption in which the corruption occurs within the block itself. this type of corruption can be either a physical corruption or logical corruption.

intrablock corruption是資料塊內部的衝突，這種衝突可能是物理的，也可能是邏輯的。

參考:Response	Intrablock Corruption	Interblock Corruption
Detection	All database utilities detect intrablock corruption, including RMAN (for example, the BACKUP command) and the DBVERIFY utility. If a database process can encounter theORA-1578 error, then it can detect the corruption and monitor it.

Only DBVERIFY and the ANALYZE statement detect interblock corruption.

參考：http://docs.oracle.com/cd/B28359_01/backup.111/b28270/rcmvalid.htm