大约有 19,000 项符合查询结果（耗时：0.0251秒） [XML]
“21天教你学会C++” - 创意 - 清泛网 - 专注C/C++及内核技术
...法（如果你已经会一门类似的语言），但你无法学到多少如何运用这些语法。简而言之，如果你是，比如说一个Basic程序员，你可以学会用C++语法写出Basic风格的程序，但你学不到C++真正的优点（和缺点）。那关键在哪里？Alan Per...
SQL Server equivalent to MySQL enum data type?
Does SQL Server 2008 have a a data-type like MySQL's enum ?
5 Answers
5
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How to upload a file in Django? [closed]
...e Django stores uploaded files and from what URL Django serves them. MEDIA_ROOT and MEDIA_URL are in settings.py by default but they are empty. See the first lines in Django Managing Files for details. Remember also set the database and add myapp to INSTALLED_APPS
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import os
BASE_DIR = os.path....
内存优化总结:ptmalloc、tcmalloc和jemalloc - 操作系统(内核) - 清泛网 - ...
...，tcmalloc性能上也有明显的优势，并且相对平稳。
github mysql优化
github使用tcmalloc后，mysql性能提升30%
Jemalloc
jemalloc是facebook推出的， 最早的时候是freebsd的libc malloc实现。 目前在firefox、facebook服务器各种组件中大量使用。
jemall...
How to find all serial devices (ttyS, ttyUSB, ..) on Linux without opening them?
... system. A trimmed down example:
# ll /sys/class/tty/ttyUSB*
lrwxrwxrwx 1 root root 0 2012-03-28 20:43 /sys/class/tty/ttyUSB0 -> ../../devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.0/ttyUSB0/tty/ttyUSB0/
lrwxrwxrwx 1 root root 0 2012-03-28 20:44 /sys/class/tty/ttyUSB1 -> ../../device...
How to copy data from one table to another new table in MySQL?
I want to copy data from one table to another in MySQL.
11 Answers
11
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What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...doesn't have to sort the output, and GROUP BY by default does. However, in MySQL even a DISTINCT+ORDER BY might still be faster than a GROUP BY due to the extra hints for the optimizer as explained by SquareCog.
– rustyx
Jan 25 '15 at 15:03
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How big can a MySQL database get before performance starts to degrade
At what point does a MySQL database start to lose performance?
15 Answers
15
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windows异常处理 __try __except - C/C++ - 清泛网 - 专注C/C++及内核技术
...进入到__except模块中运行异常处理代码
try-except的关键是如何在__except模块中获得异常错误的相关信息.
Windows提供了两个API函数来获取异常信息：
LPEXCEPTION_POINTERS GetExceptionInformation(VOID); //取得异常相关信息
DWORD GetExceptionCode(VOID...
MySQL order by before group by
...pand on my comments about using a subquery to accurate return this data.
MySQL does not force you to GROUP BY every column that you include in the SELECT list. As a result, if you only GROUP BY one column but return 10 columns in total, there is no guarantee that the other column values which bel...