Contents

require 'active_record/associations/builder/association'
require 'active_record/associations/preloader/association'

module ActiveRecord
  module Associations
    module Builder
      class Association #:nodoc:
        self.valid_options += [:preload_if]
      end
    end
    class Preloader
      class Association #:nodoc:
        def preload_filters
          [options[:preload_if]].flatten.compact
        end

        def owners_filtered
          # owners_by_key is: {1=>[#<SourceModel ...>, 2=>[#<SourceModel ...>], ...}
          owners_by_key.select do |key, records|
            preload_filters.each do |filter|
              case filter
              when Proc
                records.select!(&filter)
              when Symbol
                records.select! { |record| record.send(filter) }
              end
            end
            records.present?
          end
        end

        remove_method :associated_records_by_owner
        def associated_records_by_owner(preloader)
          owners_map = owners_filtered
          owner_keys = owners_map.keys.compact

          # Each record may have multiple owners, and vice-versa
          records_by_owner = owners.each_with_object({}) do |owner,h|
            h[owner] = []
          end

          if owner_keys.any?
            # Some databases impose a limit on the number of ids in a list (in Oracle it's 1000)
            # Make several smaller queries if necessary or make one query if the adapter supports it
            sliced  = owner_keys.each_slice(klass.connection.in_clause_length || owner_keys.size)

            records = load_slices sliced
            records.each do |record, owner_key|
              owners_map[owner_key].each do |owner|
                records_by_owner[owner] << record
              end
            end
          end

          records_by_owner
        end
      end
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
active_record_association_query_economizer-0.1.0	lib/active_record_association_query_economizer/rails4-2/associations.rb