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原创 Linux操作系统 作者:jbymy2000 时间:2012-03-19 10:00:56 0 删除 编辑
133. Which three statements are true? (Choose three.)
A. Only one LONG column can be used per table.
B. A TIMESTAMP data type column stores only time values with fractional
C. The BLOB data type column is used to store binary data in an operating
system file.
D. The minimum column width that can be specified for a varchar2 data type
column is one.
E. The value for a CHAR data type column is blank padded
Answer: ADE
Fractional:小数 blankpadded:估计是补空格的意思
The CHAR(n) datatype pads any remaining unused space with blanks to ensure that
the length of your value will always equal the value of n.
Oracle 将lob 分类为两种:
2.存储在数据库外的BFILE,不参与数据库的事务,也就是不能rollback 或commit 等,它依
BFILE 二进制文件,存储在数据库外的操作系统文件,只读的。把此文件当二进制处理。
BLOB 二进制大对象。存储在数据库里的大对象,一般是图像声音等文件。
CLOB 字符型大对象。一般存储大数量文本信息。存储单字节,固定宽度的数据。
NCLOB 字节字符大对象。存储单字节大块,多字节固定宽度,多字节变宽度数据。
The BFILE data type enables access to binary file LOBs that are stored in file systems
outside Oracle Database. A BFILE column or attribute stores a BFILE locator, which
serves as a pointer to a binary file on the server file system. The locator maintains
the directory name and the filename.

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