What does inverse_of do? What SQL does it generate?

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From the documentation, it seems like the :inverse_of option is a method for avoiding SQL queries, not generating them. It’s a hint to ActiveRecord to use already loaded data instead of fetching it again through a relationship.

Their example:

class Dungeon < ActiveRecord::Base
  has_many :traps, :inverse_of => :dungeon
  has_one :evil_wizard, :inverse_of => :dungeon
end

class Trap < ActiveRecord::Base
  belongs_to :dungeon, :inverse_of => :traps
end

class EvilWizard < ActiveRecord::Base
  belongs_to :dungeon, :inverse_of => :evil_wizard
end

In this case, calling dungeon.traps.first.dungeon should return the original dungeon object instead of loading a new one as would be the case by default.

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