new

# File activerecord/lib/active_record/insert_all.rb, line 8
    def initialize(model, inserts, on_duplicate,, returning: nil, unique_by: nil)
      raise ArgumentError, "Empty list of attributes passed" if inserts.blank?

      @model, @connection, @inserts, @keys = model, model.connection, inserts, inserts.first.keys.map(&:to_s).to_set
      @on_duplicate, @returning, @unique_by = on_duplicate, returning, unique_by

      @returning = (connection.supports_insert_returning? ? primary_keys : false) if @returning.nil?
      @returning = false if @returning == []

      @unique_by = find_unique_index_for(unique_by) if unique_by
      @on_duplicate = :skip if @on_duplicate == :update && updatable_columns.empty?

      ensure_valid_options_for_connection!
    end