大约有 2,000 项符合查询结果（耗时：0.0238秒） [XML]
Multiple Indexes vs Multi-Column Indexes
...reused.
e.g. imagine you search a table on three columns
state, county, zip.
you sometimes search by state only.
you sometimes search by state and county.
you frequently search by state, county, zip.
Then an index with state, county, zip. will be used in all three of these searches.
If yo...
C++形参与实参的区别（实例解析） - C/C++ - 清泛网 - 专注C/C++及内核技术
...实参的功能是作数据传送。发生函数调用时， 主调函数把实参的值传送给被调函数的形参从而实现主调函数向被调函数的数据传送。
1、形参变量只有在被调用时才分配内存单元，在调用结束时， 即刻释放所分配的内存单元。...
90后大学生创业凭啥估值过亿？ - 资讯 - 清泛网 - 专注C/C++及内核技术
...时发挥作用了。“虽然创业没想好一定往哪个方向，但会把自己的一个个创业目标分解出来：未来一年和三年都需要达到什么样的目标，什么时候储备资金和人才，赚来的钱是留下来进行资金积累还是分红奖励。”当时，这个学...
能把一个图片放到另一个图片上层吗？ - App应用开发 - 清泛IT社区，为创新赋能！
当然可以。
1、 图像放布局中，布局设背景图片。
2、 图像精灵放画布，画布设背景。
3、 屏幕设背景图片，图像组件放上面。
How to get first element in a list of tuples?
...
Use the zip function to decouple elements:
>>> inpt = [(1, u'abc'), (2, u'def')]
>>> unzipped = zip(*inpt)
>>> print unzipped
[(1, 2), (u'abc', u'def')]
>>> print list(unzipped[0])
[1, 2]
Edit (...
Compression/Decompression string with C#
...) != 0) {
dest.Write(bytes, 0, cnt);
}
}
public static byte[] Zip(string str) {
var bytes = Encoding.UTF8.GetBytes(str);
using (var msi = new MemoryStream(bytes))
using (var mso = new MemoryStream()) {
using (var gs = new GZipStream(mso, CompressionMode.Compress)) {...
Executing a command stored in a variable from PowerShell
...r me. Assume
7z.exe is in the system path.
$cmd = '7z.exe'
$prm = 'a', '-tzip', 'c:\temp\with space\test1.zip', 'C:\TEMP\with space\changelog'
& $cmd $prm
If the command is known (7z.exe) and only parameters are variable then this will do
$prm = 'a', '-tzip', 'c:\temp\with space\test1.zip',...
项目管理实践【六】自动同步数据库【Using Visual Studio with Source Cont...
...库，那么我们就要借助CCNET和SVN服务器，所以我们首先要把存放数据库文件、日志文件及StartKitDB.proj文件的StartKitDB文件夹，纳入到我们的版本控制中。但是，如果我们简单的把这个文件添加到我们的StartKit项目的代码库中，那么...
Pandas convert dataframe to array of tuples
...w that a dedicated feature exists). BTW, if you want normal tuples in your zip iterator (instead of namedtuples), then call: data_set.itertuples(index=False, name=None)
– Axel
Oct 25 '17 at 9:47
...
SQL query for finding records where count > 1
... named PAYMENT . Within this table I have a user ID, an account number, a ZIP code and a date. I would like to find all records for all users that have more than one payment per day with the same account number.
...