此时编写程序
require ‘mysql’
db = Mysql.real_connect(‘127.0.0.1′,’root’,’123′,’sqltest’)
res = db.query(‘select * from name’)
while row = res.fetch_row do
    puts”#{row[0]},#{row[1]}”
end

提示出错:cannot load such file — mysql/mysql_api (LoadError)

此时我们回来看gem install mysql 时提示

  At the time of building this gem, the necessaryDLL files where available
  in the following URL:

 http://dev.mysql.com/get/Downloads/Connector-C/mysql-connector-c-noinstall-6.0
.2-win32.zip/from/pick

  You can put the lib\libmysql.dll available inthis package to your Ruby bin di
rectory.

原来没有动态链接库文件
只需按照给的网址下载 解压出来libmysql.dll将它放到ruby/bin 下即可
若是windows系统也可以放到system32目录下

此时就可以正常操作数据库了