Question

所以我正在尝试对多态模型进行相对高级的查询。我有以下型号：

class Project < ActiveRecord::Base
  has_many :project_stakeholders, :dependent => :destroy
  has_many :features, :dependent => :destroy
  has_many :iterations, :dependent => :destroy
  has_many :comments, :as => :commentable, :dependent => :destroy
end

class ProjectStakeholder < ActiveRecord::Base
  belongs_to :project
  has_many :comments, :as => :commentable, :dependent => :destroy
end

class Feature < ActiveRecord::Base
  belongs_to :project
  has_many :comments, :as => :commentable, :dependent => :destroy
end

class Iteration < ActiveRecord::Base
  belongs_to :project
  has_many :comments, :as => :commentable, :dependent => :destroy
end

class User < ActiveRecord::Base
  has_many :comments, :dependent => :destroy
end

class Comment < ActiveRecord::Base
  belongs_to :commentable, :polymorphic => true
  belongs_to :created_by, :class_name => 'User'
end

我正在尝试查找current_user对特定项目的评论（project.comments，project.features.comments，project.iterations.comments，project.project_stakeholder.comments），并按created_at降序排序。

我想出的最好的是：

Class Project < ActiveRecord::Base
  def all_comments_for_user(user)
    Comment.where(:created_by_id => user.id).select { |c| c.commentable.attributes.has_key?('project_id') }.select { |c| c.commentable.project == self } | comments.where(:created_by_id => user)
  end
end

但这并没有解决降序的create_at序列。

Answer 1

Class Project < ActiveRecord::Base
  def all_comments_for_user(user)
    Comment.where(:created_by_id => user.id).order('created_at DESC').select { |c| c.commentable.attributes.has_key?('project_id') }.select { |c| c.commentable.project == self } | comments.where(:created_by_id => user)
  end
end

这有用吗？我刚刚添加了订单（'created_at DESC'）

当评论可以属于另一个可评论时，如何查询多态注释？

1 个答案: