# File lib/active_record/connection_adapters/abstract/schema_statements.rb, line 70
      def column_exists?(table_name, column_name, type = nil, options = {})
        columns(table_name).any?{ |c| c.name == column_name.to_s &&
                                      (!type                 || c.type == type) &&
                                      (!options[:limit]      || c.limit == options[:limit]) &&
                                      (!options[:precision]  || c.precision == options[:precision]) &&
                                      (!options[:scale]      || c.scale == options[:scale]) }
      end