大约有 47,000 项符合查询结果（耗时：0.0370秒） [XML]
Which one will execute faster, if (flag==0) or if (0==flag)?
...n :)
The answer is:
What is flag's type?
In the case where flag actually is a user-defined type. Then it depends on which overload of operator== is selected. Of course it can seem stupid that they would not be symmetric, but it's certainly allowed, and I have seen other abuses already.
If fl...
Exotic architectures the standards committees care about
...vers
offering backward compatibility for people who have not yet migrated all their Univac software.
Key points:
36-bit words
CHAR_BIT == 9
one's complement
72-bit non-IEEE floating point
separate address space for code and data
word-addressed
no dedicated stack pointer
Don't know if they offe...
Turn off constraints temporarily (MS SQL)
I'm looking for a way to temporarily turn off all DB's constraints (eg table relationships).
5 Answers
...
Generating CSV file for Excel, how to have a newline inside a value
...ixed the leading spaces issue in the question, I typed the CSV example manually and didn't copy-paste from a real file, the real file doesn't include those spaces, good catch.
– Nir
Aug 10 '09 at 7:41
...
SQLite Concurrent Access
...emely fast and has many clever optimizations to minimize contention. Especially SQLite 3.
For most desktop/laptop/tablet/phone applications, SQLite is fast enough as there's not enough concurrency. (Firefox uses SQLite extensively for bookmarks, history, etc.)
For server applications, somebody som...
How to create id with AUTO_INCREMENT on Oracle?
...NCREMENT by 1),
c2 VARCHAR2(10)
);
Alternatively, Oracle 12 also allows to use a sequence as a default value:
CREATE SEQUENCE dept_seq START WITH 1;
CREATE TABLE departments (
ID NUMBER(10) DEFAULT dept_seq.nextval NOT NULL,
DESCRIPTION VARCHAR2(50) NOT NULL);
ALTER T...
C++读写EXCEL文件方式比较 - C/C++ - 清泛网 - 专注C/C++及内核技术
... 上有几个开源的的EXCEL库，但是完善的不多，有的是为了PHP读写EXCEL准备的，包括libXLS，XLSlib，SmartEXCEL等。我下载了几个实验了一下，在Widonws都没有编译成功。也罢了。
4.ODBC的方式
这个亲身没有尝试过，但是按照原理，应...
我就差一个程序员了！ - 杂谈 - 清泛网 - 专注C/C++及内核技术
...需要一个程序员而已。
他们需要一个人，把想法转化成 PHP、SQL、HTML、CSS、Java 和 Javascript。这些创业者只知道他们所需要的东西。所以，他们问我，能不能帮他找上一两个计算机专业的学生加入他们的项目，做这些事情？
大...
正则表达式中 /i,/g,/m,/s,/e,/x 的含义 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...找)
/s 与/m相对，单行模式匹配。
/e 可执行模式，此为PHP专有参数，例如preg_replace函数。
/x 忽略空白模式。
这些修饰符是可以混合使用的。例如
/gi(全文查找、忽略大小写)
/ig(全文查找、忽略大小写)正则 表达式 含义
笨法玩电商网站秒杀 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...可能会引起很多连锁问题：一方面可能导致内存不足，以PHP为例，一个连接通常占用10M左右，堆积一千个连接的话，10G内存就没有了；另一方面大量的连接可能耗尽端口资源，具体取决于内核参数「net.ipv4.ip_local_port_range」。此...