ruby-on-rails - 用 OR 组合两个命名范围(而不是 AND)

Question

我想找到所有 Annotations他们的 body 是:

等于 ”？”

或

像“[？]”

做到这一点的最佳方法是什么？

我想用 SearchLogic如果可能，但 SearchLogic 允许您执行以下每项操作:

Annotation.body_equals('?')

Annotation.body_like('[?]')

您可以随时将它们链接在一起: Annotation.body_equals('?').body_like('[?]')
我不确定如何将它们与 OR 结合起来.

Note that you can combine named scopes with OR if their argument is the same.例如，我可以这样做:

 Annotation.body_equals_or_body_like('?')

但这无济于事。

请注意，我不依赖于 SearchLogic，但对于不需要打破其抽象的解决方案来说，它会很棒。

Answer 1

我找不到任何简单的解决方案，但是这个问题引起了我的兴趣，所以我推出了自己的解决方案:

class ActiveRecord::Base

  def self.or_scopes(*scopes)
    # Cleanup input
    scopes.map! do |scope|
      scope = scope.respond_to?(:to_a) ? scope.to_a : [*scope]
      scope.unshift(scope.shift.to_sym)
    end

    # Check for existence of scopes
    scopes.each{|scope| raise ArgumentError, "invalid scope: #{scope.first}" unless self.scopes.has_key?(scope.first) }

    conditions = scopes.map do |scope|
      scope = self.scopes[scope.first].call(self, *scope[1..-1])
      self.merge_conditions(scope.proxy_options[:conditions])
    end

    or_conditions = conditions.compact.join(" OR ")

    merged_scopes = scopes.inject(self){|merged, scope| merged.scopes[scope.first].call(self, *scope[1..-1]) }

    # We ignore other scope types but so does named_scopes
    find_options = merged_scopes.scope(:find).merge(:conditions => or_conditions)

    self.scoped(find_options)
  end

end

考虑以下设置:

class Person < ActiveRecord::Base
  named_scope :men,      :conditions => { :sex => 'M' }
  named_scope :women,    :conditions => { :sex => 'F' }
  named_scope :children, :conditions => "age < 18"
  named_scope :named, lambda{|name|
    { :conditions => { :name => name } }
  }
end

您可以使用一系列范围的名称来调用它:

Person.or_scopes(:women, :children)

这将返回一个这样的范围:

Person.or_scopes(:women, :children).proxy_options
# => {:conditions=>"(`people`.`sex` = 'F') OR (age < 18)"}

当范围需要参数时，您还可以使用数组数组调用它:

Person.or_scopes(:women, [:named, 'Sue']).proxy_options
# => {:conditions=>"(`people`.`sex` = 'F') OR (`people`.`name` = 'Sue')"}

在您的情况下，Horace，您可以使用以下内容:

Annotation.or_scopes([:body_equals, '?'], [:body_like, '[?']).all