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How to work with complex numbers in C?
...introduced in mathematics, from the need of calculating negative quadratic roots. Complex number concept was taken by a variety of engineering fields.
Today that complex numbers are widely used in advanced engineering domains such as physics, electronics, mechanics, astronomy, etc...
Real and imag...
What is the difference between single and double quotes in SQL?
...ct_id
SELECT PRODUCT.id 'product_id'
Either works in Oracle, SQL Server, MySQL… but I know some have said that the TOAD IDE seems to give some grief when using the single quotes approach.
You do have to use single quotes when the column alias includes a space character, e.g., product id, but it...
提升大数据分析思想，拥抱大数据未来 - 资讯 - 清泛网 - 专注C/C++及内核技术
...务和世界范围内产生的数据。而所谓公司的麻烦是指，该如何正确利用这些数据——判断出哪些才是相关的、有用的，哪些是需要过滤掉的。最重要的是，哪些才是有助于推动业务发展的。”
因此，思想转变的第一步应是观察...
mysql command for showing current configuration variables
Can not find a command that displays the current configuration of mysql from within the database.
3 Answers
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How to redirect to a 404 in Rails?
... to do it yourself. If your application hijacks all of the routes from the root. It's bad design, but sometimes un-avoidable.
– ablemike
Oct 3 '11 at 13:54
9
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How to get ER model of database from server with Workbench
...y to get an ER model of a database from the server that is connected to my MySQL Workbench?
4 Answers
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MySQL, better to insert NULL or empty string?
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Better to Insert NULL for consistency in your database in MySQL. Foreign keys can be stored as NULL but NOT as empty strings.
You will have issues with an empty string in the constraints.
You may have to insert a fake record with a unique empty string to satisfy a Foreign Key cons...
cpuid汇编指令 - C/C++ - 清泛网 - 专注C/C++及内核技术
...一组返回的是基本信息，另一组返回的是扩展信息。
1、如何判断CPU是否支持CPUID指令
前面说过，大概是从80486开始才有的cpuid这个指令，是不是所有的80486家族CPU都有这个指令我也不是很清楚，但在EFLAGS中的bit 21可以识别CPU...
How do I get the current date and time in PHP?
...tetime;
$now = new DateTime();
echo $now->format('Y-m-d H:i:s'); // MySQL datetime format
echo $now->getTimestamp(); // Unix Timestamp -- Since PHP 5.3
And to specify the timezone:
$now = new DateTime(null, new DateTimeZone('America/New_York'));
$now->setTimezone(new DateTi...
MySQL Select Query - Get only first 10 characters of a value
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Using the below line
SELECT LEFT(subject , 10) FROM tbl
MySQL Doc.
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