# File lib/active_record/connection_adapters/abstract/schema_definitions.rb, line 146
        def value_to_decimal(value)
          # Using .class is faster than .is_a? and
          # subclasses of BigDecimal will be handled
          # in the else clause
          if value.class == BigDecimal
            value
          elsif value.respond_to?(:to_d)
            value.to_d
          else
            value.to_s.to_d
          end
        end