Module | ActiveRecord::Reflection::ClassMethods
In: | lib/active_record/reflection.rb

Reflection allows you to interrogate Active Record classes and objects about their associations and aggregations. This information can, for example, be used in a form builder that took an Active Record object and created input fields for all of the attributes depending on their type and displayed the associations to other objects.

You can find the interface for the AggregateReflection and AssociationReflection classes in the abstract MacroReflection class.

### Methods

create_reflection reflect_on_aggregation reflect_on_all_aggregations reflect_on_all_associations reflect_on_association reflections

### Public Instance methods

create_reflection(macro, name, options, active_record)
reflect_on_aggregation(aggregation)

Returns the AggregateReflection object for the named `aggregation` (use the symbol). Example:

      Account.reflect_on_aggregation(:balance) # returns the balance AggregateReflection

reflect_on_all_aggregations()

Returns an array of AggregateReflection objects for all the aggregations in the class.

reflect_on_all_associations(macro = nil)

Returns an array of AssociationReflection objects for all the associations in the class. If you only want to reflect on a certain association type, pass in the symbol (`:has_many`, `:has_one`, `:belongs_to`) for that as the first parameter. Example:

      Account.reflect_on_all_associations             # returns an array of all associations
      Account.reflect_on_all_associations(:has_many)  # returns an array of all has_many associations

reflect_on_association(association)

Returns the AssociationReflection object for the named `association` (use the symbol). Example:

      Account.reflect_on_association(:owner) # returns the owner AssociationReflection
      Invoice.reflect_on_association(:line_items).macro  # returns :has_many

reflections()

Returns a hash containing all AssociationReflection objects for the current class Example:

      Invoice.reflections
      Account.reflections

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