使用ftp –i <ip>
或者prompt命令关闭Interactive mode
2009年5月19日星期二
Sorting Multilingual Data
Oracle9i之前,中文是按照二进制编码进行排序的。在oracle9i中新增了按照拼音、部首、笔画排序功能。
1、设置NLS_SORT参数值
SCHINESE_RADICAL_M 按照部首(第一顺序)、笔划(第二顺序)排序
SCHINESE_STROKE_M 按照笔划(第一顺序)、部首(第二顺序)排序
SCHINESE_PINYIN_M 按照拼音排序
2、Session级别的设置,修改ORACLE字段的默认排序方式:
按拼音:alter session set nls_sort = SCHINESE_PINYIN_M;
按笔画:alter session set nls_sort = SCHINESE_STROKE_M;
按偏旁:alter session set nls_sort = NLS_SORT=SCHINESE_RADICAL_M;
3、语句级别设置排序方式:
按照笔划排序
select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_STROKE_M');
按照部首排序
select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_RADICAL_M');
按照拼音排序,此为系统的默认排序方式
select * from dept order by nlssort(name,'NLS_SORT=SCHINESE_PINYIN_M');
4、修改系统参数(数据库所在操作系统):
set NLS_SORT=SCHINESE_RADICAL_M ;export NLS_SORT (sh)
setenv NLS_SORT SCHINESE_RADICAL_M (csh)
HKLC\SOFTWARE\ORACLE\home0\NLS_SORT (win注册表)
Oracle 官方说明
NLS_SORT NLS_SORT specifies the collating sequence for ORDER BY queries. NLS_COMP NLS_COMP specifies the collation behavior of the database session.
Property
Description
Parameter type
String
Syntax
NLS_SORT = { BINARY | linguistic_definition }
Default value
Derived from NLS_LANGUAGE
Modifiable
ALTER SESSION
Range of values
BINARY or any valid linguistic definition name
- If the value is BINARY, then the collating sequence for ORDER BY queries is based on the numeric value of characters (a binary sort that requires less system overhead).
-
If the value is a named linguistic sort, sorting is based on the order of the defined linguistic sort. Most (but not all) languages supported by the NLS_LANGUAGE parameter also support a linguistic sort with the same name.
Note:
Setting NLS_SORT to anything other than BINARY causes a sort to use a full table scan, regardless of the path chosen by the optimizer. BINARY is the exception because indexes are built according to a binary order of keys. Thus the optimizer can use an index to satisfy the ORDER BY clause when NLS_SORT is set to BINARY. If NLS_SORT is set to any linguistic sort, the optimizer must include a full table scan and a full sort in the execution plan.
You must use the NLS_SORT operator with comparison operations if you want the linguistic sort behavior.
Property
Description
Parameter type
String
Syntax
NLS_COMP = { BINARY | LINGUISTIC | ANSI }
Default value
BINARY
Modifiable
ALTER SESSION
Basic
No
Values:
- BINARY
Normally, comparisons in the WHERE clause and in PL/SQL blocks is binary unless you specify the NLSSORT function.
- LINGUISTIC
Comparisons for all SQL operations in the WHERE clause and in PL/SQL blocks should use the linguistic sort specified in the NLS_SORT parameter. To improve the performance, you can also define a linguistic index on the column for which you want linguistic comparisons.
- ANSI
A setting of ANSI is for backwards compatibility; in general, you should set NLS_COMP to LINGUISTIC
2009年5月18日星期一
FLT_EPSILON
FLT_EPSILON
This is the minimum positive floating point number of type float
such that 1.0 + FLT_EPSILON != 1.0
is true. It's supposed to be no greater than 1E-5
. 2009年5月13日星期三
《潜伏》中的一段对话
余则成:是觉得无路可走了吗?
晚秋:(哭,点头)
余:其实你面前有一条通往未来的路啊。(秋流泪摇头)值得你活下去。那一路很美好,就像你的诗歌一样。怎么会觉得无路可走了呢?
秋:你愿意娶我吗?
余:比娶你更美好。还多了一份自由。你不是最向往自由吗?
秋:(点头)
余:你也知道我的身份了。你愿意去吗?
秋:那我就再也见不到你了。
余:那儿有很多人都像我一样。那是另一个世界,好地方,好风光。你那么年轻,那么漂亮,可以选择的。你想想,晚秋,你站在一列雄壮的队伍里,迈着大步,高唱着战歌,去改变整个中国,那是什么气势?一个小小的余则成,就是路边的一个送行者,你看见了他,他看见了你,你们挥挥手就过去了。再往前就是更有意义的生活。沮丧吗?无非就是一个小布尔乔亚的无病呻吟。留恋它就是一种高度近视。有时候看得远一点,不就什么都有了么。包括爱。