如何为belongs_to禁用default_scope？

Question

有没有办法禁用default_scope单个belongs_to关联？该default_scope是好的,但所有的单一belongs_to,我想绕过范围.我很熟悉,with_exclusive_scope但我认为不能与belongs_to一起使用.

有什么建议？

上下文:我试图允许acts_as_revisable中的branch_source关联指向不是最新的修订(是错误的).revisable_is_current

Answer 1

可能有点迟到(仅短短3年),但只是遇到了同样的问题,Tobias的解决方案肯定是正确的方向,但它可以简化为Rails 3.2+.我唯一不喜欢的是Document的"硬编码"类名,也许可以使用反射来改变......

无论如何这就是我想出来的:

class Comment < ActiveRecord::Base
  # Document has some kind of default_scope
  belongs_to :document

  # Ensure document is not scoped, because Rails 3.2 uses modules it's
  # possible to use simple inheritance.
  def document
    Document.unscoped { super }
  end
end

更新:基于reflect_on_association https://gist.github.com/2923336获得通用解决方案

Answer 2

belongs_to :account, -> { unscope(where: :destroyed_at) }

适用于我,Rails 4.1

Answer 3

我自己刚遇到这个问题,这就是我想出的:

class Comment < ActiveRecord::Base
  belongs_to :document # Document has some kind of default scope
                       # that stops us from finding it

  # Override getter method for document association
  def document_with_unscoped
    # Fetch document with default scope disabled
    Document.unscoped { document_without_unscoped }
  end
  alias_method_chain :document, :unscoped
end