Ruby on rails 在RubyonRails3中创建通用模型时出现的问题

我正在尝试创建一个“通用模型”，这样它就可以连接到任何数据库的任何表。首先，我创建了这个类，它连接到另一个指定的数据库（不使用模式）

Db

class Db < ActiveRecord::Base

    self.abstract_class = true

    attr_accessor :error

    def initialize(item = nil)
        @error = ""
        connect
        super
    end

    def connect
        could_connect = true
        @error = ""

        begin
            ActiveRecord::Base.establish_connection(
              :adapter  => "mysql2",
              :host     => "localhost",
              :username => "root",
              :password => "",
              :database => "another_database", 
              :port => 3306,
              :encoding => "utf8"
            )
        rescue ActiveRecord::ConnectionNotEstablished
            @error = "Could not connect to database. The connection was not established"
            could_connect = false
        rescue Mysql2::Error
            @error = "Could not connect to database using MySQL2"
            could_connect = false
        rescue => e
            @error = "Could not connect to database. #{e.message}."
            could_connect = false
        end

        return could_connect
    end

end

有什么不对劲吗？有没有更好的办法？提前谢谢

为什么不简单地在运行时避免所有的麻烦

t = 'some_table'
c = Class.new(ActiveRecord::Base) { self.table_name = t }

然后，

c

为

某些表

引用AR类，您可以执行以下操作：

o = c.find(1)
# 'o' is now a wrapper for the row of some_table where 'id = 1'

cols = c.columns.map(&:name)
# 'cols' is now an array of some_table's column names

这是Ruby，其中类也是对象

如果需要连接到另一个数据库，则可以将

建立\u连接

调用与

自身表\u名称

一起放入块中：

t = 'some_table'
d = 'some_other_database'
c = Class.new(ActiveRecord::Base) do
    establish_connection(:adapter => 'mysql2', :database => d, ...)
    self.table_name = t
end

---

抽象类Db的用途是什么？您曾经是Java开发人员吗？非常感谢，太棒了！这看起来很像我可以用来解决的问题-如果您能看一下并给我一些建议，我将不胜感激。Rails 4不支持匿名ActiveRecord类：@JonathanNesbitt您有什么解决方法吗？也许使用eval或exec方法中的一种会让人不快。或者抛弃ActiveRecord，选择更灵活的方式。

t = 'some_table'
c = Class.new(ActiveRecord::Base) { self.table_name = t }

o = c.find(1)
# 'o' is now a wrapper for the row of some_table where 'id = 1'

cols = c.columns.map(&:name)
# 'cols' is now an array of some_table's column names

t = 'some_table'
d = 'some_other_database'
c = Class.new(ActiveRecord::Base) do
    establish_connection(:adapter => 'mysql2', :database => d, ...)
    self.table_name = t
end