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数据挖掘——分词入门 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...了解数据挖掘的目的：发现数据中价值。这个才是关键，如何发现数据中的价值。那什么是数据呢？比如大家要上网首先需要输入网址，打开网页后会自动判断哪些是图片、哪些是新闻、哪些是用户名称、游戏图标等。人大脑可...
Add Foreign Key to existing table
...is link. It has helped me with errno 150:
http://verysimple.com/2006/10/22/mysql-error-number-1005-cant-create-table-mydbsql-328_45frm-errno-150/
On the top of my head two things come to mind.
Is your foreign key index a unique name in the whole database (#3 in the list)?
Are you trying to set th...
华为公司的新产品研发流程管理 - 项目管理 - 清泛网 - 专注C/C++及内核技术
...以企业的研发环节为例，技术纷繁复杂，更新变幻莫测，如何决策?如何投资?如何预算控制、...引言：高效率和高质量似乎永远是一对解不开的矛盾。以企业的研发环节为例，技术纷繁复杂，更新变幻莫测，如何决策?如何投资?...
MySQL Error 1215: Cannot add foreign key constraint
...the 4th point was my problem. It's kind of nasty - but I'm very very happy mysql did crash for that
– Sebas
Jun 16 '16 at 15:21
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show 10 mo...
Database development mistakes made by application developers [closed]
... exists--you should be using it.
It's quite common to see this failure on MySQL databases. I don't believe MyISAM supports it. InnoDB does. You'll find people who are using MyISAM or those that are using InnoDB but aren't using it anyway.
More here:
How important are constraints like NOT NULL...
Retrieving the last record in each group - MySQL
...
MySQL 8.0 now supports windowing functions, like almost all popular SQL implementations. With this standard syntax, we can write greatest-n-per-group queries:
WITH ranked_messages AS (
SELECT m.*, ROW_NUMBER() OVER (PARTIT...
一分钟明白 VS manifest 原理 - C/C++ - 清泛网 - 专注C/C++及内核技术
...不知加载哪个，于是manifest文件来指明。
manifest在哪儿，如何创建。
如果用VS开发，可以Set通过porperty->configuration properties->linker->manifest file->Generate manifest To Yes来自动创建manifest来指定系统的和CRT的assembly版本。
除了这样产生外...
What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
...cally, a lot of dbms have been quite poor when it comes to handling joins (MySQL being a particularly noteworthy example). So n+1 has, often, been notably faster than a join. And then there are ways to improve on n+1 but still without needing a join, which is what the original problem relates to.
H...
mysql check collation of a table
...
Works for me in mysql 5.5.52. ...) ENGINE=InnoDB AUTO_INCREMENT=24 DEFAULT CHARSET=latin1 My guess is it may not show the collation if it is set to the default for the database in later versions of mysql/mariadb.
– Deve...
社会化海量数据采集爬虫框架搭建 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...数据采集爬虫框架搭建随着BIG DATA大数据概念逐渐升温，如何搭建一个能够采集海量数据的架构体系摆在大家眼前。如何能够做到所见即所得的无阻拦式采集、如何快 随着BIG DATA大数据概念逐渐升温，如何搭建一个能够采集海...