Ruby 连接 Mysql _ MySql2

前面一章节我们介绍了 Ruby DBI 的使用。这章节我们技术 Ruby 连接 Mysql 更高效的驱动 mysql2,目前也推荐使用这种方式连接 MySql。

安装 mysql2 驱动:

gem install mysql2

你需要使用 –with-mysql-config 配置 mysql_config 的路径,如: –with-mysql-config=/some/random/path/bin/mysql_config

连接

连接数据库语法如下:

client = Mysql2::Client.new(:host => "localhost", :username => "root")

更多参数可以查看 http://api.rubyonrails.org/classes/ActiveRecord/ConnectionAdapters/MysqlAdapter.html

查询

results = client.query("SELECT * FROM users WHERE group='githubbers'")

特殊字符转义

escaped = client.escape("gi'thu\"bbe\0r's")
results = client.query("SELECT * FROM users WHERE group='#{escaped}'")

计算结果集返回的数量:

results.count

迭代结果集:

results.each do |row|
 # row 是哈希
 # 键值是数据库字段
 # 值都是对应 MySQL中数据
 puts row["id"] # row["id"].class == Fixnum
 if row["dne"] # 不存在则是 nil
 puts row["dne"]
 end
end

实例

#!/usr/bin/ruby -w
require 'mysql2'
 
client = Mysql2::Client.new(
 :host => '127.0.0.1', # 主机
 :username => 'root', # 用户名
 :password => '123456', # 密码
 :database => 'test', # 数据库
 :encoding => 'utf8' # 编码
 )
results = client.query("SELECT VERSION()")
results.each do |row|
 puts row
end

以上实例运行输出结果为:

{"VERSION()"=>"5.6.21"}

连接选项

Mysql2::Client.new(
 :host,
 :username,
 :password,
 :port,
 :database,
 :socket = '/path/to/mysql.sock',
 :flags = REMEMBER_OPTIONS | LONG_PASSWORD | LONG_FLAG | TRANSACTIONS | PROTOCOL_41 | SECURE_CONNECTION | MULTI_STATEMENTS,
 :encoding = 'utf8',
 :read_timeout = seconds,
 :write_timeout = seconds,
 :connect_timeout = seconds,
 :reconnect = true/false,
 :local_infile = true/false,
 :secure_auth = true/false,
 :default_file = '/path/to/my.cfg',
 :default_group = 'my.cfg section',
 :init_command => sql
 )

更多内容请参阅:http://www.rubydoc.info/gems/mysql2/0.2.3/frames

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