    # File lib/active_record/fixtures.rb, line 552
      def insert_fixtures
        now = ActiveRecord::Base.default_timezone == :utc ? Time.now.utc : Time.now
        now = now.to_s(:db)

        # allow a standard key to be used for doing defaults in YAML
        if is_a?(Hash)
          delete('DEFAULTS')
        else
          delete(assoc('DEFAULTS'))
        end

        # track any join tables we need to insert later
        habtm_fixtures = Hash.new do |h, habtm|
          h[habtm] = HabtmFixtures.new(@connection, habtm.options[:join_table], nil, nil)
        end

        each do |label, fixture|
          row = fixture.to_hash

          if model_class && model_class < ActiveRecord::Base
            # fill in timestamp columns if they aren't specified and the model is set to record_timestamps
            if model_class.record_timestamps
              timestamp_column_names.each do |name|
                row[name] = now unless row.key?(name)
              end
            end

            # interpolate the fixture label
            row.each do |key, value|
              row[key] = label if value == "$LABEL"
            end

            # generate a primary key if necessary
            if has_primary_key_column? && !row.include?(primary_key_name)
              row[primary_key_name] = Fixtures.identify(label)
            end

            # If STI is used, find the correct subclass for association reflection
            reflection_class =
              if row.include?(inheritance_column_name)
                row[inheritance_column_name].constantize rescue model_class
              else
                model_class
              end

            reflection_class.reflect_on_all_associations.each do |association|
              case association.macro
              when :belongs_to
                # Do not replace association name with association foreign key if they are named the same
                fk_name = (association.options[:foreign_key] || "#{association.name}_id").to_s

                if association.name.to_s != fk_name && value = row.delete(association.name.to_s)
                  if association.options[:polymorphic]
                    if value.sub!(/\s*\(([^\)]*)\)\s*$/, "")
                      target_type = $1
                      target_type_name = (association.options[:foreign_type] || "#{association.name}_type").to_s

                      # support polymorphic belongs_to as "label (Type)"
                      row[target_type_name] = target_type
                    end
                  end

                  row[fk_name] = Fixtures.identify(value)
                end
              when :has_and_belongs_to_many
                if (targets = row.delete(association.name.to_s))
                  targets = targets.is_a?(Array) ? targets : targets.split(/\s*,\s*/)
                  join_fixtures = habtm_fixtures[association]

                  targets.each do |target|
                    join_fixtures["#{label}_#{target}"] = Fixture.new(
                      { association.primary_key_name => row[primary_key_name],
                        association.association_foreign_key => Fixtures.identify(target) },
                      nil, @connection)
                  end
                end
              end
            end
          end

          @connection.insert_fixture(fixture, @table_name)
        end

        # insert any HABTM join tables we discovered
        habtm_fixtures.values.each do |fixture|
          fixture.delete_existing_fixtures
          fixture.insert_fixtures
        end
      end