# File lib/arel/insert_manager.rb, line 16
    def insert fields
      return if fields.empty?

      if String === fields
        @ast.values = SqlLiteral.new(fields)
      else
        @ast.relation ||= fields.first.first.relation

        values = []

        fields.each do |column, value|
          @ast.columns << column
          values << value
        end
        @ast.values = Nodes::Values.new values, @ast.columns
      end
    end