469.Which of the following NLS_SORT parameter values would result in case-insensitive and
accent-insensitive binary sorts?
A. NLS_SORT = BINARY
B. NLS_SORT = BINARY_AI
C. NLS_SORT = BINARY_CI
D. NLS_SORT = BINARY_AI_CI
E. Binary sorts are case insensitive and accent insensitive by default.
Answer: B
答案解析：
参考：http://docs.oracle.com/cd/E11882_01/timesten.112/e21643/attribute.htm#TTREF179
NLS_SORT
The NLS_SORT attribute indicates which collating sequence to use for linguistic comparisons. It accepts the values listed in "Supported Linguistic Sorts." All these values can be modified to do case-insensitive
sorts by appending _CI to the value. To perform accent-insensitive and case-insensitive sorts, append _AI to the value.
For materialized views and cache groups, TimesTen recommends that you explicitly specify the collating sequence using the NLSSORT SQL function rather than using this attribute in the connection string or DSN definition.
Operations involving character comparisons support linguistic case-sensitive collating sequences. Case-insensitive sorts may affect DISTINCT value interpretation.
NLS_SORT may affect many operations. The supported operations that are sensitive to collating sequence are:
-
MIN,MAX -
BETWEEN -
=,<>,>,>=,<,<= -
DISTINCT -
CASE -
GROUP BY -
HAVING -
ORDER BY -
IN -
LIKE
Only BINARY sort is supported with the TIMESTEN8 character set.
NLS_SORT settings other than BINARY may have significant performance impact on character operations.
Note:
Primary key indexes are always based on theBINARY collating sequence. Use of non-BINARY NLS_SORT equality searches cannot use the primary key index