小编Jos*_*ald的帖子

如何创建具有多个依赖于同一个父级的关联的工厂？

父模型：

class Parent < ActiveRecord::Base
  has_many :codes
  has_many :parent_filters

  validates :parent, :presence => true, :uniqueness => true
end

菲特勒模型：

class Filter < ActiveRecord::base
  has_many :parent_filters
  validates :filter, :presence => true, :uniqueness => true
end

ParentFilter 连接模型：

class ParentFilter < ActiveRecord
  belongs_to :parent
  belongs_to :filter

  validates :filter, :presence => true
  validates :parent, :filter, :presence => true, :uniqueness => [ :scope => filter ]
end

AdhocAttribute 模型：

class AdhocAttribute < ActiveRecord::Base
  has_many :adhoc_mappings

  has_many :codes, :through => :adhoc_mappings
  has_many :parent_filters, :through …

大多数在线资料都有这样的初始化:

class MyClass
  attr_accessors :a, :b, :c
  def initialize(a,b,c)
    @a = a
    @b = b
    @c = c
  end
end

有或没有默认值.创建一个新实例是:

n = MyClass.new(1,2,3)
n.a # => 1
n.b # => 2
n.c # => 3

我想知道如何使用哈希语法初始化实例,如:

n = MyClass.new(:a => 1, :b => 2, :c => 3)

这相当于:

n = MyClass.new(:b => 2, :a => 1, :c => 3)

这难以实施吗？