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"bber‘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