您可以使用Reflection中的reflection_on_all_associations方法例如：

Thing.reflect_on_all_associations(:belongs_to)

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您可以使用类的reflections哈希来完成此操作。可能有更简单的方法，但这是有效的：

# say you have a class Thing
class Thing < ActiveRecord::Base
  belongs_to :foo
  belongs_to :bar
end

# this would return a hash of all `belongs_to` reflections, in this case:
# { :foo => (the Foo Reflection), :bar => (the Bar Reflection) }
reflections = Thing.reflections.select do |association_name, reflection| 
  reflection.macro == :belongs_to
end

# And you could iterate over it, using the data in the reflection object, 
# or just the key.
#
# These should be equivalent:
thing = Thing.first
reflections.keys.map {|association_name| thing.send(association_name) }
reflections.values.map {|reflection| thing.send(reflection.name) }

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Thing.reflections.collect{|a, b| b.class_name if b.macro==:belongs_to}.compact 
#=> ["Foo", "Bar"]

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当然，您也可以传递：has_many或任何其他关联

最新消息：
在Rails 7上运行，该方法现在是：

Thing._reflections

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