（239）Evaluate the following command:

SQL>ALTER SYSTEM SET db_securefile = 'IGNORE';

What is the impact of this setting on the usage of SecureFiles?

A. It forces BasicFiles to be created even if the SECUREFILE option is specified to create the LOB.

B. It forces SecureFiles to be created even if the BASICFILE option is specified to create the LOB.

C. It does not allow the creation of SecureFiles and generates an error if the SECUREFILE option is specified to create the LOB.

D. It ignores the SECUREFILE option only if a Manual Segment Space Management tablespace is used and creates a BasicFile.

答案：（A）

解析：

DB_SECUREFILE = {NEVER | PERMITTED | ALWAYS | IGNORE}

1. NEVER

指定为SecureFiles的LOB都被创建为BasicFile LOBs.

所有SecureFile LOB特定的存储选项和功能(例如, compress,encrypt,deduplicate)都会引起异常.

BasicFile LOB的默认值将被用于没有指定的存储选项

2. PERMITTED

LOBs允许被创建为SecureFiles

3. ALWAYS

试图创建所有的LOBs为SecureFile LOBs,但不是自动段空间管理的表空间中的LOBs将被创建为,除非SECUREFILE被显示指定.

任何指定的BasicFile LOB存储选项将被忽略,并且SecureFile LOB的默认值将用于没有指定的存储选项

4. IGNORE

SECUREFILE关键字和所有的SECUREFILE选项被忽略