QUESTION NO: 46
Which three statements are true regarding the data types in Oracle Database 10g/11g? (Choose three.)
A. The BLOB data type column is used to store binary data in an operating system file
B. The minimum column width that can be specified for a VARCHAR2 data type column is one
C. A TIMESTAMP data type column stores only time values with fractional seconds
D. The value for a CHAR data type column is blank-padded to the maximum defined columnwidth
E. Only One LONG column can be used per table
Answer: B,D,E
答案解析：
参考：20：http://blog.csdn.net/rlhua/article/details/12911331
Explanation:
LONG Character data in the database character set, up to 2GB. All the functionality of LONG
(and more) is provided by CLOB; LONGs should not be used in a modern database, and if your
database has any columns of this type they should be converted to CLOB. There can only be one
LONG column in a table.
DVARCHAR2 Variable-length character data, from 1 byte to 4KB. The data is stored in the
database character set. The VARCHAR2 data type must be qualified with a number indicating the
maximum length of the column.
If a value is inserted into the column that is less than this, it is not a problem: the value will only
take up as much space as it needs. If the value is longer than this maximum, the INSERT will fail
with an error. VARCHAR2(size)
Variable-length character data (A maximum size must be specified: minimum size is 1; maximum
size is 4,000.)
BLOB Like CLOB, but binary data that will not undergo character set conversion by Oracle Net.
BFILE A locator pointing to a file stored on the operating system of the database server. The size
of the files is limited to 4GB.
TIMESTAMP This is length zero if the column is empty, or up to 11 bytes, depending on the
precision specified.
Similar to DATE, but with precision of up to 9 decimal places for the seconds, 6 places by default.