Rails - 视图模型关联

Question

我有这样的模型：

class Person
has_many :groups
has_many :group_memberships, :foreign_key => "member_id"
end

class Group_Membership
belongs_to :member, :class_name => 'Person'
belongs_to :group
end

class Group
belongs_to :person
has_many :group_memberships
has_many :members, :class_name => "Person", :through => "group_memberships", :foreign_key => "member_id"

有人请求membership，并使用status false 创建它的模型。 group 的所有者在他的person#show 页面上可以看到谁请求了membership 以及他参与的groups。由于groups 和group_memberships belongs_to 一个person，但group_membership 还有belongs_to 一个group，我怎样才能在person#show 中创建一个视图，允许person 看到谁问过对于memberships 上的groups 和person 自己，还有什么groups 和person 有一个membership？

##EDIT##

这里的status 默认为false，因为如果所有者edit 此状态并将其设置为true，group 将只接受person。

取自这个问题的想法：Question about Association and Models on Rails

Answer 1

这里有一些伪代码，我认为它们会让你走上你想要的道路：https://gist.github.com/981513

class Person
    has_many :groups
    has_many :group_memberships, :foreign_key => "member_id", :through => :groups

    scope :owned_groups, where(:is_owner => true).joins(:group_memberships) # gets all groups where this person is owner
end

class Group_Membership
    belongs_to :member, :class_name => 'Person'
    belongs_to :group

    # note that these attributes need to be defined
    # is_owner (boolean)
    # member_approved (boolean)

    scope :requested, :where(:member_approved => false)
end

class Group
    belongs_to :person
    has_many :group_memberships
    has_many :members, :class_name => "Person", :through => "group_memberships", :foreign_key => "member_id"
end

公平的警告，我根本没有测试过，我还在学习新的 AR 模式 :)

我认为您的 group_memberships 关系可能最适合作为 :through 关系，然后围绕该关系可能具有的不同“状态”创建范围。您也可以查看state machine 以获得一些帮助。

Answer 2

我是这么认为的

class Person
  has_many :groups
  has_many :group_memberships, :foreign_key => "member_id"
  has_many :own_groups, :class_name => "Group", :through => "group_memberships", :foreign_key => "group_id"

end

class Group_Membership
  belongs_to :member, :class_name => 'Person'
  belongs_to :group
end

class Group
  belongs_to :person
  has_many :group_memberships
  has_many :asked_group_memberships, :class_name => 'Group_Membership', :conditions => ['status = ?', false]
  has_many :members, :class_name => "Person", :through => "group_memberships", :foreign_key => "member_id", :conditions => ['group_memberships.status = ?', true]
end