Install mysql ruby gem

env: ubuntu

首先需要安装 mysql dev library

sudo apt-get install libmysqlclient15-dev

 不然直接sudo gem install mysql会报错:

l-config=/usr/local/mysql/bin/mysql_config
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb --with-mysql-config=/usr/local/mysql/bin/mysql_config
extconf.rb:10: command not found: /usr/local/mysql/bin/mysql_config --cflags
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers. Check the mkmf.log file for more
details. You may need configuration options.
...

 然后：

sudo gem install mysql

 如果你是通过sudo apt-get install ruby安装的ruby，那么可能开始会出现以下错误是：

`require': no such file to load -- mkmf (LoadError)

 使用

sudo apt-get install ruby1.8-dev

 安装ruby可以避免这个问题。

然后写一段代码看看是否已经ok了：

require 'rubygems'
require 'mysql'

def with_db
	dbh = Mysql.real_connect('localhost','root','xxxxxx','deal')
	begin
		yield dbh
	ensure
		dbh.close
	end
end

with_db do |db|
	res = db.query('select * from route limit 2')
	res.each{ |row| row.each{|field| puts field } }
	res.free
end