Is there a way to list all belongs_to associations?

Question

I need to list all belongs_to associations in a model object and iterate through them. Is there a way to do this?

Answer 1

You can make use of reflect_on_all_associations method from Reflection For example:

Thing.reflect_on_all_associations(:belongs_to) 

Answer 2

You could make use of the class's reflections hash to do this. There may be more straightforward ways, but this works:

# 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) } 

Answer 3

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

of course, you can pass :has_many, or any other associations too