Ruby 连接 Mysql – MySql2
最后更新于：2022-03-27 01:22:09
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}’")
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
# 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
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
)
: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
)