method

construct_join_attributes

Ruby on Rails latest stable (v7.1.3.2) - 0 notes - Class: ThroughAssociation

construct_join_attributes(*records) private

Construct attributes for :through pointing to owner and associate. This is used by the methods which create and delete records on the association.

We only support indirectly modifying through associations which have a belongs_to source. This is the “has_many :tags, through: :taggings” situation, where the join model typically has a belongs_to on both side. In other words, associations which could also be represented as has_and_belongs_to_many associations.

We do not support creating/deleting records on the association where the source has some other type, because this opens up a whole can of worms, and in basically any situation it is more natural for the user to just create or modify their join records directly as required.

Show source

# File activerecord/lib/active_record/associations/through_association.rb, line 57
        def construct_join_attributes(*records)
          ensure_mutable

          association_primary_key = source_reflection.association_primary_key(reflection.klass)

          if Array(association_primary_key) == reflection.klass.composite_query_constraints_list && !options[:source_type]
            join_attributes = { source_reflection.name => records }
          else
            assoc_pk_values = records.map { |record| record._read_attribute(association_primary_key) }
            join_attributes = { source_reflection.foreign_key => assoc_pk_values }
          end

          if options[:source_type]
            join_attributes[source_reflection.foreign_type] = [ options[:source_type] ]
          end

          if records.count == 1
            join_attributes.transform_values!(&:first)
          else
            join_attributes
          end
        end

construct_join_attributes

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