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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...
Nginx serves .php files as downloads, instead of executing them
...ttps://www.digitalocean.com/community/tutorials/how-to-install-linux-nginx-mysql-php-lemp-stack-on-ubuntu-14-04 but when I try to run some .php file it's just downloading it...
for example... http://5.101.99.123/info.php it's working but... If I go to the main http://5.101.99.123 it's downloadi...
mysql check collation of a table
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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...
PDO Prepared Inserts multiple rows in single query
I am currently using this type of SQL on MySQL to insert multiple rows of values in one single query:
22 Answers
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技术人员如何创业《四》- 打造超强执行力团队 - 资讯 - 清泛网 - 专注C/C++...
技术人员如何创业《四》- 打造超强执行力团队好的团队是创业公司成功的必要因素之一。差劲的团队会导致整个团队没有战斗力，互相算计，只看到自己的利益，永远做不成一个好的产品。优秀 好的团队是创业公司成功的必...
CMake使用教程 - C/C++ - 清泛网 - 专注C/C++及内核技术
...中找到这个手册对应的代码。
1、Step1。
（如果不知道如何使用cmake，以及如何使用编译产生的Turorial.exe，可先看下前面“CMake使用步骤”的说明，它以Step4为例详细介绍了使用过程，Step1的配置可能不够完全，比如无法运行make...
How do I rename a column in a database table using SQL?
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This is not supported in MySQL, is it?
– ustun
Oct 21 '11 at 11:41
5
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How to execute a raw update sql with dynamic binding in rails
...d try accessing the underlying connection and using it's methods, e.g. for MySQL:
st = ActiveRecord::Base.connection.raw_connection.prepare("update table set f1=? where f2=? and f3=?")
st.execute(f1, f2, f3)
st.close
I'm not sure if there are other ramifications to doing this (connections left op...
创业者如何发现开放却未知的秘密 - 资讯 - 清泛网 - 专注C/C++及内核技术
创业者如何发现开放却未知的秘密所谓开放却未知的秘密，其实就在用户手上，在用户口中，就在数据里面。最近几篇专栏一直在围绕需求这个主题展开，从第一篇的人性，第二篇的最美投资往往在眨眼之间，到第三篇的敬畏街...
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...