在has_many中通过中间属性查找：在Rails中

Question

  

可能重复：
  Rails has_many :through Find by Extra Attributes in Join Model

我的模型中有以下多对多的设置：

class Project < ActiveRecord::Base
  has_many :projectcollaborations
  has_many :partners, :through => :projectcollaborations, :source => :partner
end

class Partner < ActiveRecord::Base
  has_many :projectcollaborations
  has_many :projects, :through => :projectcollaborations, :source => :project
end

class Projectcollaboration < ActiveRecord::Base
  belongs_to :project
  belongs_to :partner
end

我可以访问：

@partner = Partner.first
@partner.projects
@partner.projectcollaborations.find_by_myrole('creator')
....

现在如何在多对多关系表中访问@partner所有拥有myrole创建者的项目？

Answer 1

@collaborations = @partner.projectcollaborations.includes(:projects).find_all_by_myrole('creator')
@projects = @collaborations.map &:project

也许还有另一种更漂亮，更有轨道的方式，但这就是我要做的事情